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author | Anton Luka Šijanec <anton@sijanec.eu> | 2024-11-18 00:18:24 +0100 |
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committer | Anton Luka Šijanec <anton@sijanec.eu> | 2024-11-18 00:18:24 +0100 |
commit | 5ddc2e50dcfe5a1e36bb5a04008e29a33a661921 (patch) | |
tree | 50d520ad03f3f267aa7f6504c6e15d9106b97ae6 /šola/komb/teor.lyx | |
parent | aps1dn2: zlivanje (diff) | |
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Diffstat (limited to 'šola/komb/teor.lyx')
-rw-r--r-- | šola/komb/teor.lyx | 7105 |
1 files changed, 7105 insertions, 0 deletions
diff --git a/šola/komb/teor.lyx b/šola/komb/teor.lyx new file mode 100644 index 0000000..5f60d51 --- /dev/null +++ b/šola/komb/teor.lyx @@ -0,0 +1,7105 @@ +#LyX 2.4 created this file. For more info see https://www.lyx.org/ +\lyxformat 620 +\begin_document +\begin_header +\save_transient_properties true +\origin unavailable +\textclass article +\begin_preamble +\usepackage{hyperref} +\usepackage{siunitx} +\usepackage{pgfplots} +\usepackage{listings} +\usepackage{multicol} +\sisetup{output-decimal-marker = {,}, quotient-mode=fraction, output-exponent-marker=\ensuremath{\mathrm{3}}} +\usepackage{amsmath} +\usepackage{tikz} +\newcommand{\udensdash}[1]{% + \tikz[baseline=(todotted.base)]{ + \node[inner sep=1pt,outer sep=0pt] (todotted) {#1}; + \draw[densely dashed] (todotted.south west) -- (todotted.south east); + }% +}% +\DeclareMathOperator{\Lin}{\mathcal Lin} +\DeclareMathOperator{\rang}{rang} +\DeclareMathOperator{\sled}{sled} +\DeclareMathOperator{\Aut}{Aut} +\DeclareMathOperator{\red}{red} +\DeclareMathOperator{\karakteristika}{char} +\DeclareMathOperator{\Ker}{Ker} +\DeclareMathOperator{\Slika}{Ker} +\DeclareMathOperator{\sgn}{sgn} +\DeclareMathOperator{\End}{End} +\DeclareMathOperator{\n}{n} +\DeclareMathOperator{\Col}{Col} +\usepackage{algorithm,algpseudocode} +\providecommand{\corollaryname}{Posledica} +\usepackage[slovenian=quotes]{csquotes} +\end_preamble +\use_default_options true +\begin_modules +enumitem +theorems-ams +theorems-ams-extended +\end_modules +\maintain_unincluded_children no +\language slovene +\language_package default +\inputencoding auto-legacy +\fontencoding auto +\font_roman "default" "default" +\font_sans "default" "default" +\font_typewriter "default" "default" +\font_math "auto" "auto" +\font_default_family default +\use_non_tex_fonts false +\font_sc false +\font_roman_osf false +\font_sans_osf false +\font_typewriter_osf false +\font_sf_scale 100 100 +\font_tt_scale 100 100 +\use_microtype false +\use_dash_ligatures true +\graphics default +\default_output_format default +\output_sync 0 +\bibtex_command default +\index_command default +\float_placement H +\float_alignment class +\paperfontsize default +\spacing single +\use_hyperref true +\pdf_bookmarks true +\pdf_bookmarksnumbered false +\pdf_bookmarksopen false +\pdf_bookmarksopenlevel 1 +\pdf_breaklinks false +\pdf_pdfborder false +\pdf_colorlinks false +\pdf_backref false +\pdf_pdfusetitle true +\papersize default +\use_geometry true +\use_package amsmath 1 +\use_package amssymb 1 +\use_package cancel 1 +\use_package esint 1 +\use_package mathdots 1 +\use_package mathtools 1 +\use_package mhchem 1 +\use_package stackrel 1 +\use_package stmaryrd 1 +\use_package undertilde 1 +\cite_engine basic +\cite_engine_type default +\biblio_style plain +\use_bibtopic false +\use_indices false +\paperorientation portrait +\suppress_date false +\justification false +\use_refstyle 1 +\use_formatted_ref 0 +\use_minted 0 +\use_lineno 0 +\index Index +\shortcut idx +\color #008000 +\end_index +\leftmargin 2cm +\topmargin 2cm +\rightmargin 2cm +\bottommargin 2cm +\headheight 2cm +\headsep 2cm +\footskip 1cm +\secnumdepth 3 +\tocdepth 3 +\paragraph_separation indent +\paragraph_indentation default +\is_math_indent 0 +\math_numbering_side default +\quotes_style german +\dynamic_quotes 0 +\papercolumns 1 +\papersides 1 +\paperpagestyle default +\tablestyle default +\tracking_changes false +\output_changes false +\change_bars false +\postpone_fragile_content false +\html_math_output 0 +\html_css_as_file 0 +\html_be_strict false +\docbook_table_output 0 +\docbook_mathml_prefix 1 +\end_header + +\begin_body + +\begin_layout Title +Teorija Kombinatorike — + IŠRM 2024/25 +\end_layout + +\begin_layout Author + +\noun on +Anton Luka Šijanec +\end_layout + +\begin_layout Date +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +today +\end_layout + +\end_inset + + +\end_layout + +\begin_layout Abstract +Povzeto po zapiskih s predavanj profesorja Konvalinke. +\end_layout + +\begin_layout Standard +\begin_inset CommandInset toc +LatexCommand tableofcontents + +\end_inset + + +\end_layout + +\begin_layout Section +Osnovni principi kombinatorike +\end_layout + +\begin_layout Standard +Pri tem predmetu velja +\begin_inset Formula $\mathbb{N}\coloneqq\mathbb{N}_{0}$ +\end_inset + + ZDB +\begin_inset Formula $0\in\mathbb{N}$ +\end_inset + +. +\end_layout + +\begin_layout Subsection +Funkcija/preslikava +\end_layout + +\begin_layout Definition* +\begin_inset Formula $f:X\to Y$ +\end_inset + + je formalno množica parov +\begin_inset Formula $f\subseteq X\times Y$ +\end_inset + + s pogojem +\begin_inset Formula $\forall x\in X\exists!y\in Y\ni:\left(x,y\right)\in f$ +\end_inset + + ZDB za vsak +\begin_inset Formula $x\in X$ +\end_inset + + je +\begin_inset Formula $f\left(x\right)$ +\end_inset + + enolično definiran. +\end_layout + +\begin_layout Standard +Funkcijo podamo tako, + da: +\end_layout + +\begin_layout Enumerate +naštejemo vse elemente +\begin_inset Formula $f$ +\end_inset + + — + vse pare (puščični diagram med množicama) +\end_layout + +\begin_layout Enumerate +povemo predpis za preslikanje elementa — + +\begin_inset Formula $f:\mathbb{N}\to\mathbb{N};x\mapsto x^{2}$ +\end_inset + + +\end_layout + +\begin_layout Enumerate +z rekurzijo — + +\begin_inset Formula $f:\mathbb{N}\to\mathbb{N},f\left(0\right)=1,f\left(1\right)=1,f\left(n\right)=f\left(n-1\right)+f\left(n-2\right)$ +\end_inset + + za +\begin_inset Formula $n\geq2$ +\end_inset + + (fibbonaccijevo zaporedje) +\end_layout + +\begin_layout Definition* +Zaporedje je preslikava iz naravnih števil v katerokoli neprazno množico. +\end_layout + +\begin_layout Standard +\begin_inset Separator plain +\end_inset + + +\end_layout + +\begin_layout Definition* +Lastnosti preslikav. + Naj bo +\begin_inset Formula $f:A\to B$ +\end_inset + + preslikava. +\end_layout + +\begin_deeper +\begin_layout Itemize +\begin_inset Formula $f$ +\end_inset + + injektivna +\begin_inset Formula $\Leftrightarrow\forall a\in A,b\in B:f\left(a\right)=f\left(b\right)\Rightarrow a=b$ +\end_inset + + +\end_layout + +\begin_layout Itemize +\begin_inset Formula $f$ +\end_inset + + surjektivna +\begin_inset Formula $\Leftrightarrow\forall a\in A\exists b\in B\ni:f\left(b\right)=a$ +\end_inset + + +\end_layout + +\begin_layout Itemize +\begin_inset Formula $f$ +\end_inset + + bijektivna +\begin_inset Formula $\Leftrightarrow\forall a\in A\exists!b\in B\ni:f\left(b\right)=a$ +\end_inset + + ZDB +\begin_inset Formula $f$ +\end_inset + + injektivna in +\begin_inset Formula $f$ +\end_inset + + surjektivna hkrati +\end_layout + +\end_deeper +\begin_layout Standard +\begin_inset Separator plain +\end_inset + + +\end_layout + +\begin_layout Definition* +Kombinatorika je odkrivanje moči množic. + Tu često želimo dokazati enakost moči dveh množic, + najlepše to storimo s konstrukcijo bijekcije, + saj velja: +\end_layout + +\begin_layout Theorem* +Naj bo +\begin_inset Formula $f:X\to Y$ +\end_inset + +. +\end_layout + +\begin_layout Itemize +\begin_inset Formula $f$ +\end_inset + + injektivna +\begin_inset Formula $\Rightarrow\left|X\right|\leq\left|Y\right|$ +\end_inset + + +\end_layout + +\begin_layout Itemize +\begin_inset Formula $f$ +\end_inset + + surjektivna +\begin_inset Formula $\Rightarrow\left|Y\right|\leq\left|X\right|$ +\end_inset + + +\end_layout + +\begin_layout Itemize +\begin_inset Formula $f$ +\end_inset + + bijektivna +\begin_inset Formula $\Rightarrow\left|X\right|=\left|Y\right|$ +\end_inset + + +\end_layout + +\begin_layout Standard +Imejmo +\begin_inset Formula $n$ +\end_inset + + kroglic in +\begin_inset Formula $k$ +\end_inset + + škatel. + Vsako kroglico damo v eno od teh škatel. + Postavitev kroglic v škatle je preslikava iz množice kroglic v množico škatel ( +\begin_inset Formula $\left\{ 1..5\right\} \to\left\{ a,b,c\right\} $ +\end_inset + +). + Injektivnost te preslikave pomeni, + da ni praznih škatel, + surjektivnost pa da je v vsaki škatli vsaj ena kroglica. +\end_layout + +\begin_layout Definition* +Nekaj oznak v kombinatoriki: +\end_layout + +\begin_deeper +\begin_layout Itemize +\begin_inset Formula $\mathbb{N}\coloneqq\left\{ 0,1,2,\dots\right\} \sim$ +\end_inset + + možne moči končnih množic +\end_layout + +\begin_layout Itemize +\begin_inset Formula $\left[n\right]\coloneqq\left\{ 1..n\right\} $ +\end_inset + +, + +\begin_inset Formula $\left[0\right]\coloneqq\emptyset$ +\end_inset + +, + +\begin_inset Formula $\left|\left[n\right]\right|=n$ +\end_inset + + +\end_layout + +\begin_layout Itemize +množica podmnožic +\begin_inset Formula $A$ +\end_inset + + (potenčna množica +\begin_inset Formula $A$ +\end_inset + +) +\begin_inset Formula $\eqqcolon2^{A}$ +\end_inset + +, + velja +\begin_inset Formula $\left|2^{A}\right|=2^{\left|A\right|}$ +\end_inset + +, + odtod tudi ta oznaka +\end_layout + +\begin_layout Itemize +množica preslikav +\begin_inset Formula $X\to Y\eqqcolon Y^{X}$ +\end_inset + +, + saj +\begin_inset Formula $\left|Y^{X}\right|=\left|Y\right|^{\left|X\right|}$ +\end_inset + +. +\end_layout + +\begin_layout Itemize +\begin_inset Formula $\sum_{k}\sim$ +\end_inset + + vsota po vseh +\begin_inset Formula $k\in\mathbb{N}$ +\end_inset + +, + +\begin_inset Formula $\sum_{k\geq a}\sim$ +\end_inset + + vsota po vseh +\begin_inset Formula $k\in\mathbb{N},k\geq a$ +\end_inset + + +\end_layout + +\end_deeper +\begin_layout Theorem* +Binomski izrek. +\begin_inset Formula +\[ +\left(1+x\right)^{n}=\sum_{k=0}^{n}\binom{n}{k}x^{k} +\] + +\end_inset + + +\end_layout + +\begin_layout Subsection +Dirichletovo načelo (angl. + Pigeonhole principle) +\end_layout + +\begin_layout Standard +Če obstaja injekcija +\begin_inset Formula $X\to Y$ +\end_inset + +, + je +\begin_inset Formula $\left|X\right|\leq\left|Y\right|$ +\end_inset + +. + Če torej +\begin_inset Formula $\left|X\right|\geq\left|Y\right|$ +\end_inset + +, + ne obstaja injekcija +\begin_inset Formula $X\to Y$ +\end_inset + +. + Če imamo +\begin_inset Formula $n$ +\end_inset + + kroglic v +\begin_inset Formula $k$ +\end_inset + + škatlah in +\begin_inset Formula $n>k$ +\end_inset + +, + bosta gotovo vsaj v eni škatli vsaj dve kroglici. +\end_layout + +\begin_layout Paragraph +Uporaba načela +\end_layout + +\begin_layout Itemize +ob trinajstih ljudeh imata vsaj dva rojstni dan v istem mesecu. + Kroglice so ljudje, + škatle so meseci, + preslikava je iz človeka v mesec rojstva. +\end_layout + +\begin_layout Itemize +\begin_inset Formula $X\subseteq\mathbb{N}$ +\end_inset + +; + +\begin_inset Formula $\left|X\right|=n+1$ +\end_inset + +. + +\begin_inset Formula $\exists x,y\in X\ni:n\vert\left(x-y\right)\wedge x\not=y$ +\end_inset + +. + Trditev je ekvivalentna temu, + da sta v +\begin_inset Formula $X$ +\end_inset + + dve števili z istim ostankom pri deljenju z +\begin_inset Formula $n$ +\end_inset + +. + Kroglice so števila, + škatle so možni ostanki pri deljenju z +\begin_inset Formula $n$ +\end_inset + +. + Preslikava +\begin_inset Formula $x\mapsto x\mod n$ +\end_inset + +. + Kroglic je +\begin_inset Formula $n+1$ +\end_inset + +, + škatel je +\begin_inset Formula $n\Rightarrow$ +\end_inset + + po dirichletu trditev velja. +\end_layout + +\begin_layout Itemize +\begin_inset Formula $n$ +\end_inset + + ljudi. + Trdimo, + da +\begin_inset Formula $\exists2$ +\end_inset + + človeka, + ki poznata enako število ljudi. + Imamo torej +\begin_inset Formula $n$ +\end_inset + + kroglic — + ljudi in +\begin_inset Formula $n$ +\end_inset + + škatel — + št. + poznanstev ( +\begin_inset Formula $\in\left\{ 0..\left(n-1\right)\right\} $ +\end_inset + +). + Preslikava preslika človeka v število njegovih znancev. + Sicer velja +\begin_inset Formula $n=n$ +\end_inset + +, + toda ne moremo imeti hkrati nekoga, + ki pozna 0 oseb in hkrati nekoga, + ki pozna +\begin_inset Formula $n-1$ +\end_inset + + oseb, + torej je število različnih poznanstev največ +\begin_inset Formula $n-1$ +\end_inset + +. + Dirichlet pove, + da obstaja dve osebi, + ki poznata enako število ljudi. +\end_layout + +\begin_layout Itemize +\begin_inset Formula $X\subseteq\left\{ 1..100\right\} $ +\end_inset + +; + +\begin_inset Formula $\left|X\right|=10$ +\end_inset + +. + Trdimo, + da obstajata dve disjunktni podmnožici +\begin_inset Formula $X$ +\end_inset + +, + ki imata enako vsoto. + Kroglice so podmnožice +\begin_inset Formula $X$ +\end_inset + + — + +\begin_inset Formula $2^{10}=1024$ +\end_inset + + jih je. + Škatle so možne vsote elementov, + torej +\begin_inset Formula $\in\left\{ 55..955\right\} $ +\end_inset + +. + Injekcije iz podmnožic +\begin_inset Formula $X$ +\end_inset + + dolžine 10 v možne vsote po dirichletu ni, + zato obstajata vsaj dve podmnožici, + ki imata isto vsoto. + Če sta nedisjunktni, + jima odstranimo presek, + pa dobimo disjunktni, + ne da bi spremenili vsoto elementov. +\end_layout + +\begin_layout Itemize +\begin_inset Formula $X\subseteq\left\{ 1..2n\right\} $ +\end_inset + +; + +\begin_inset Formula $\left|X\right|=n+1$ +\end_inset + +. + Trdimo, + da +\begin_inset Formula $\exists x,x'\in X\ni:x|x'\wedge x\not=x'$ +\end_inset + +. + Kroglice so +\begin_inset Formula $X$ +\end_inset + +. + Za katerokoli število velja +\begin_inset Formula $x=2^{a}\cdot b$ +\end_inset + +, + kjer je +\begin_inset Formula $b$ +\end_inset + + liho. + Škatle so liha števila v +\begin_inset Formula $\left[2n\right]$ +\end_inset + +. + Preslikava slika +\begin_inset Formula $x\to b$ +\end_inset + + za +\begin_inset Formula $b$ +\end_inset + + od prej. + Ker je kroglic več kot škatel, + velja +\begin_inset Formula $\exists x,x'\in X\ni:x=2^{a}b\wedge x'=2^{a'}b$ +\end_inset + +. + Če je +\begin_inset Formula $a<a'$ +\end_inset + +, + je +\begin_inset Formula $x'\vert x$ +\end_inset + +, + sicer je +\begin_inset Formula $x\vert x'$ +\end_inset + +. +\end_layout + +\begin_layout Subsection +Načelo vsote in produkta +\end_layout + +\begin_layout Theorem* +Načelo vsote. + Naj bosta +\begin_inset Formula $A,B$ +\end_inset + + množici. + Če sta disjunktni, + +\begin_inset Formula $\left|A\cup B\right|=\left|A\right|+\left|B\right|$ +\end_inset + +. + Če nista nujno disjunktni, + velja +\begin_inset Formula $\left|A\cup B\right|=\left|A\right|+\left|B\right|-\left|A\cap B\right|$ +\end_inset + +. + Splošneje: + +\begin_inset Formula $A_{1},\dots,A_{n}$ +\end_inset + + disjunktne +\begin_inset Formula $\Rightarrow\left|\bigcup_{k=1}^{n}A_{k}\right|=\sum_{k=1}^{n}\left|A_{k}\right|$ +\end_inset + +. +\end_layout + +\begin_layout Standard +Interpretacija: + Če so elementi množice bodisi tipa 1 bodisi tipa 2 (ne pa obeh hkrati), + je skupno število vsota števila elementov tipa 1 in števila elementov tipa 2. +\end_layout + +\begin_layout Standard +\begin_inset Separator plain +\end_inset + + +\end_layout + +\begin_layout Theorem* +Načelo produkta. + Naj bosta +\begin_inset Formula $A,B$ +\end_inset + + množici. + +\begin_inset Formula $\left|A\times B\right|=\left|A\right|\cdot\left|B\right|$ +\end_inset + +. + Splošneje: + +\begin_inset Formula $A_{1},\dots,A_{n}$ +\end_inset + + množice +\begin_inset Formula $\Rightarrow\left|\Pi_{k=1}^{n}A_{k}\right|=\Pi_{k=1}^{n}\left|A_{k}\right|$ +\end_inset + +. +\end_layout + +\begin_layout Standard +\begin_inset Separator plain +\end_inset + + +\end_layout + +\begin_layout Theorem* +Interpretacija: + Izberemo element iz +\begin_inset Formula $A$ +\end_inset + + na toliko načinov, + kolikor je elementov +\begin_inset Formula $A$ +\end_inset + +, + nato še neodvisno od prve izbire izberemo element iz +\begin_inset Formula $B$ +\end_inset + + itd. +\end_layout + +\begin_layout Example* +Primeri. +\end_layout + +\begin_layout Itemize +oblačenje. + Bodisi formalno bodisi neformalno (pravilo vsote). + Formalna oprava sestoji iz ene izmed enajstih srajc in enih izmed petih hlač, + neformalna pa iz ene izmed devetinpetdesetih majic in enih izmed štirih kavbojk (pravili produkta). + Možnih oprav je torej +\begin_inset Formula $11\cdot5+59\cdot4=55+236=291$ +\end_inset + +. +\end_layout + +\begin_layout Itemize +\begin_inset Formula $n-$ +\end_inset + +mestna števila, + ki vsebujejo štirico in same različne števke. + Štirica je lahko na enem izmed +\begin_inset Formula $n$ +\end_inset + + mest (pravilo vsote). + Za preostale števke pa uporabimo varianto načela produkta, + kjer število možnih izbir ni odvisno od prej izbranih elementov. + Iskanih števil je +\begin_inset Formula $\frac{9!}{\left(10-n\right)!}+\left(n-1\right)\frac{8!\cdot8}{\left(10-n\right)!}$ +\end_inset + + (levi člen za štirico na prvem mestu, + desni člen za štirico na preostalih +\begin_inset Formula $n-1$ +\end_inset + + mestih). +\end_layout + +\begin_layout Itemize +figure pri šahu razporedimo po 1. + vrsti: + +\begin_inset Formula $8$ +\end_inset + + za tekača 1 in +\begin_inset Formula $7$ +\end_inset + + za tekača 2 (skupaj +\begin_inset Formula $56/2$ +\end_inset + + — + lovcev medsebojno ne ločimo), + +\begin_inset Formula $6$ +\end_inset + + za konja 1 in +\begin_inset Formula $5$ +\end_inset + + za konja 2 (skupaj +\begin_inset Formula $30/2$ +\end_inset + +), + +\begin_inset Formula $4$ +\end_inset + + za trdnjavo 1 in +\begin_inset Formula $3$ +\end_inset + + za trdnjavo 2 (skupaj +\begin_inset Formula $12/2$ +\end_inset + +), + +\begin_inset Formula $2$ +\end_inset + + za kraljico in 1 za kralja (skupaj +\begin_inset Formula $2$ +\end_inset + +). + Torej je možnih razporeditev +\begin_inset Formula $\frac{56}{2}\cdot\frac{30}{2}\cdot\frac{12}{2}\cdot2=5040$ +\end_inset + +. +\end_layout + +\begin_layout Itemize +Fischerjev naključni šah (chess960). + Figure so naključno razporejene po prvi vrsti z naslednjimi omejitvami: + tekača sta na različnih barvah, + kralj je med trdnjavama (da dopustimo rošadi). + +\begin_inset Formula $4$ +\end_inset + + za tekača 1 in +\begin_inset Formula $4$ +\end_inset + + za tekača 2 (skupaj +\begin_inset Formula $8$ +\end_inset + +), + +\begin_inset Formula $6$ +\end_inset + + za konja 1 in +\begin_inset Formula $5$ +\end_inset + + za konja 2 (skupaj +\begin_inset Formula $30/2=15$ +\end_inset + +), + +\begin_inset Formula $4$ +\end_inset + + za kraljico in 1 za trdnjavi in kralja (preostanejo le še tri nedodeljena mesta). + Torej je možnih razporeditev = +\begin_inset Formula $8\cdot15\cdot4=960$ +\end_inset + +. +\end_layout + +\begin_layout Itemize +dokaži +\begin_inset Formula $\left|2^{A}\right|=2^{\left|A\right|}$ +\end_inset + + za končno množico +\begin_inset Formula $A\sim$ +\end_inset + + najdi bijekcijo +\begin_inset Formula $\Phi$ +\end_inset + + med +\begin_inset Formula $\left\{ 0,1\right\} ^{\left|A\right|}\tilde{=}\left\{ 0..2^{\left|A\right|}-1\right\} $ +\end_inset + + in +\begin_inset Formula $2^{A}$ +\end_inset + +. + +\begin_inset Formula $\Phi^{-1}\left(B\right)=\left\{ a_{i}\in A;B_{i}=1\right\} $ +\end_inset + +, + +\begin_inset Formula $\Phi\left(B\right)=\left(a_{1}\in B,a_{2}\in B,\dots,a_{n}\in B\right)$ +\end_inset + +. + Velja +\begin_inset Formula $\Phi^{-1}\circ\Phi=id$ +\end_inset + + in +\begin_inset Formula $\Phi\circ\Phi^{-1}=id$ +\end_inset + +. + S kombinatoriko pa lahko to dokažemo malce bolj intuitivno. + Za vsak element se odločimo, + ali je v podmnožici al,i ne. + 2 izbiri za vsakega in izbire so neodvisne +\begin_inset Formula $\Rightarrow2^{\left|A\right|}$ +\end_inset + +. +\end_layout + +\begin_layout Definition* +Permutacija +\begin_inset Formula $X$ +\end_inset + + je bijekcija +\begin_inset Formula $X\to X$ +\end_inset + +. + Množica permutacij +\begin_inset Formula $X$ +\end_inset + + je +\begin_inset Formula $S_{X}$ +\end_inset + + ali +\begin_inset Formula $S\left(X\right)$ +\end_inset + +. + Množica permutacij +\begin_inset Formula $\left[n\right]$ +\end_inset + + je +\begin_inset Formula $S_{\left[n\right]}$ +\end_inset + + ali +\begin_inset Formula $S_{n}$ +\end_inset + +. + Permutacijo zapišemo z dvovrstično notacijo, + primer: + +\begin_inset Formula $\left(\begin{array}{ccccc} +1 & 2 & 3 & 4 & 5\\ +2 & 4 & 3 & 1 & 5 +\end{array}\right)$ +\end_inset + +, + ali pa z enovrstično, + primer: + +\begin_inset Formula $\begin{array}{ccccc} +2 & 4 & 3 & 1 & 5\end{array}$ +\end_inset + +. +\end_layout + +\begin_layout Standard +\begin_inset Separator plain +\end_inset + + +\end_layout + +\begin_layout Definition* +\begin_inset Formula $a_{n}\sim b_{n}$ +\end_inset + + ( +\begin_inset Formula $\left(a_{n}\right)_{n\in\mathbb{N}}$ +\end_inset + + je asimptotsko enako +\begin_inset Formula $\left(b_{n}\right)_{n\in\mathbb{N}}$ +\end_inset + +) +\begin_inset Formula $\Leftrightarrow\lim_{n\to\infty}\frac{a_{n}}{b_{n}}=1$ +\end_inset + +. +\end_layout + +\begin_layout Standard +\begin_inset Separator plain +\end_inset + + +\end_layout + +\begin_layout Definition* +\begin_inset Formula $n!=n\cdot\left(n-1\right)!$ +\end_inset + + za +\begin_inset Formula $n\geq1$ +\end_inset + +, + +\begin_inset Formula $0!=1$ +\end_inset + + +\end_layout + +\begin_layout Theorem* +Velja +\begin_inset Formula $\left|S_{n}\right|=n\cdot\left(n-1\right)\cdot\cdots\cdot\left(n-\left(n-1\right)\right)=n!$ +\end_inset + + +\end_layout + +\begin_layout Fact* +Stirlingova formula. + +\begin_inset Formula $n!\sim\left(\frac{n}{3}\right)^{n}\cdot\sqrt{2\sqrt{n}}$ +\end_inset + +, + kjer +\begin_inset Formula $\sim$ +\end_inset + + predstavlja asimptotsko enakost. +\end_layout + +\begin_layout Standard +Permutacije lahko medsebojno komponiramo. + Temu pravimo množenje. +\end_layout + +\begin_layout Example* +\begin_inset Formula $\begin{array}{ccccc} +4 & 1 & 3 & 2 & 5\end{array}\circ\begin{array}{ccccc} +1 & 4 & 3 & 5 & 2\end{array}=\begin{array}{ccccc} +4 & 2 & 3 & 5 & 1\end{array}$ +\end_inset + + +\end_layout + +\begin_layout Theorem* +Za +\begin_inset Formula $A$ +\end_inset + + množico vseh permutacij neke množice je +\begin_inset Formula $\left(A,\circ\right)$ +\end_inset + + grupa. +\end_layout + +\begin_layout Proof +Dokažimo le asociativnost, + obstoj enote in inverz: +\end_layout + +\begin_deeper +\begin_layout Itemize +\begin_inset Formula $\left(\pi\circ\varphi\right)\circ\tau=\pi\circ\left(\varphi\circ\tau\right)$ +\end_inset + + +\end_layout + +\begin_layout Itemize +\begin_inset Formula $\pi\circ id=id\circ\pi=\pi$ +\end_inset + + +\end_layout + +\begin_layout Itemize +\begin_inset Formula $\forall\pi\in A\exists\tau\in A\ni:\pi\circ\tau=\tau\circ\pi=id$ +\end_inset + + +\end_layout + +\end_deeper +\begin_layout Remark* +Velja +\begin_inset Formula $\left|S_{n}\right|=n$ +\end_inset + +. + Naj bo +\begin_inset Formula $\pi\in S_{n}$ +\end_inset + +, + +\begin_inset Formula $k\in\left[n\right]$ +\end_inset + +. + Oglejmo si zaporedje +\begin_inset Formula $k,\pi k,\pi^{2}k,\dots$ +\end_inset + +. + Po dirichletu +\begin_inset Formula $\exists i>j\ni:\pi^{i}\left(k\right)=\pi^{j}\left(k\right)\Rightarrow\pi^{j-i}\left(k\right)=k$ +\end_inset + + in imamo ciklično zaporedje +\begin_inset Formula $k,\pi k,\pi^{2}k,\dots,k$ +\end_inset + +. + Cikel označimo z +\begin_inset Formula $\left(k,\pi k,\dots,k\right)$ +\end_inset + +. +\end_layout + +\begin_layout Corollary* +Vsaka permutacija je produkt disjunktnih ciklov. +\begin_inset Formula +\[ +\left(\begin{array}{cccccccc} +1 & 2 & 3 & 4 & 5 & 6 & 7 & 8\\ +4 & 2 & 7 & 6 & 3 & 8 & 1 & 5 +\end{array}\right)=\left(1,4,6,8,5,3,7\right)\left(2\right)=\left(1,4,6,8,5,3,7\right) +\] + +\end_inset + +Disjunktni cikli medsebojno komutirajo. + Cikel je invarianten za ciklično shiftanje/zamikanje/vrtenje. + Do vrstnega reda ciklov in znotrajciklične ureditve je zapis permutacije kot produkt disjunktnih ciklov enoličen. +\end_layout + +\begin_layout Claim* +Naj bosta +\begin_inset Formula $N,K$ +\end_inset + + množici, + +\begin_inset Formula $\left|N\right|=n,\left|K\right|=k$ +\end_inset + +. +\end_layout + +\begin_deeper +\begin_layout Enumerate +Preslikav iz +\begin_inset Formula $N$ +\end_inset + + v +\begin_inset Formula $K$ +\end_inset + + je +\begin_inset Formula $\left|K^{N}\right|=\left|K\right|^{\left|N\right|}$ +\end_inset + +. +\end_layout + +\begin_layout Enumerate +Injektivnih preslikav iz +\begin_inset Formula $N$ +\end_inset + + v +\begin_inset Formula $K$ +\end_inset + + je +\begin_inset Formula $k\left(k-1\right)\left(k-2\right)\cdots\left(k-n+1\right)\eqqcolon k^{\underline{n}}$ +\end_inset + + (pravimo +\begin_inset Formula $k$ +\end_inset + + na +\begin_inset Formula $n$ +\end_inset + + padajoče) +\end_layout + +\end_deeper +\begin_layout Proof +Intuitiven dokaz. + Naj bo +\begin_inset Formula $N=\left\{ x_{1},\dots,x_{n}\right\} $ +\end_inset + + +\end_layout + +\begin_deeper +\begin_layout Enumerate +Za vsak +\begin_inset Formula $x_{i}$ +\end_inset + + imamo +\begin_inset Formula $k$ +\end_inset + + izbir, + kam se bo preslikal in izbire so neodvisne: + +\begin_inset Formula $k\cdot\cdots\cdot k=k^{n}$ +\end_inset + +. +\end_layout + +\begin_layout Enumerate +Za +\begin_inset Formula $x_{1}$ +\end_inset + + je +\begin_inset Formula $k$ +\end_inset + + izbir, + za +\begin_inset Formula $x_{2}$ +\end_inset + + je +\begin_inset Formula $k-1$ +\end_inset + + izbir itd. + Če je +\begin_inset Formula $\left|K\right|>\left|N\right|$ +\end_inset + +, + bomo na neki točki vse skupaj množili z 0 in dobili 0, + s čimer ustrezamo dirichletu. +\end_layout + +\begin_layout Standard +\begin_inset Note Note +status open + +\begin_layout Plain Layout +Formalnejši dokaz. +\end_layout + +\begin_layout Enumerate +Iščemo bijekcijo med +\begin_inset Formula $K^{N}$ +\end_inset + + in +\begin_inset Formula $\left[k\right]^{n}$ +\end_inset + + TODO XXX FIXME +\end_layout + +\end_inset + + +\end_layout + +\end_deeper +\begin_layout Section +Podmnožice in načrti +\end_layout + +\begin_layout Subsection +Binomski koeficienti +\end_layout + +\begin_layout Definition* +Naj bo +\begin_inset Formula $k,n\in\mathbb{N}$ +\end_inset + +, + +\begin_inset Formula $A$ +\end_inset + + množica. + +\begin_inset Formula ${A \choose k}\coloneqq\left\{ B\subseteq A;\left|B\right|=k\right\} $ +\end_inset + + ZDB vse +\begin_inset Formula $k-$ +\end_inset + +elementne podmnožice +\begin_inset Formula $A$ +\end_inset + +. +\end_layout + +\begin_layout Example* +\begin_inset Formula ${\left[4\right] \choose 2}=\left\{ \left\{ 1,2\right\} ,\left\{ 1,3\right\} ,\left\{ 1,4\right\} ,\left\{ 2,3\right\} ,\left\{ 2,4\right\} ,\left\{ 3,4\right\} \right\} $ +\end_inset + +, + +\begin_inset Formula ${\left[4\right] \choose 4}=\left\{ \left\{ 1,2,3,4\right\} \right\} $ +\end_inset + +, + +\begin_inset Formula ${\left[4\right] \choose 1}=\left\{ \left\{ 1\right\} ,\left\{ 2\right\} ,\left\{ 3\right\} ,\left\{ 4\right\} \right\} $ +\end_inset + +, + +\begin_inset Formula ${\left[4\right] \choose 0}=\left\{ \left\{ \right\} \right\} =\left\{ \emptyset\right\} $ +\end_inset + +, + +\begin_inset Formula ${\left[4\right] \choose -1}=\left\{ \right\} =\emptyset$ +\end_inset + +, + +\begin_inset Formula $\bigcup_{k=0}^{\left|A\right|}{A \choose k}=2^{A}$ +\end_inset + +. +\end_layout + +\begin_layout Definition* +Binomski koeficient/simbol. + Naj bo +\begin_inset Formula $n,k\in\mathbb{N}$ +\end_inset + +. + +\begin_inset Formula ${n \choose k}\coloneqq\left|{\left[n\right] \choose k}\right|$ +\end_inset + +. + Rečemo +\begin_inset Formula $n$ +\end_inset + + nad +\begin_inset Formula $k$ +\end_inset + + (angl. + +\begin_inset Formula $n$ +\end_inset + + choose +\begin_inset Formula $k$ +\end_inset + +). +\end_layout + +\begin_layout Example* +\begin_inset Formula ${n \choose 0}=1$ +\end_inset + +, + +\begin_inset Formula ${n \choose 1}=n$ +\end_inset + +, + +\begin_inset Formula ${n \choose 2}=\frac{n\left(n-1\right)}{2}$ +\end_inset + + (neurejeni pari) +\end_layout + +\begin_layout Claim* +\begin_inset Formula +\[ +{n \choose n-k}={n \choose k} +\] + +\end_inset + + +\end_layout + +\begin_layout Proof +Bijekcija +\begin_inset Formula $\Phi:{\left[n\right] \choose k}\to\binom{\left[n\right]}{n-k}$ +\end_inset + + s predpisom +\begin_inset Formula $\Phi\left(B\right)=B^{\mathcal{C}}$ +\end_inset + + in +\begin_inset Formula $\Phi^{-1}\left(B\right)=B^{\mathcal{C}}$ +\end_inset + +. +\end_layout + +\begin_layout Claim* +\begin_inset Formula +\[ +{n \choose k}=\frac{n^{\underline{k}}}{k!}=\begin{cases} +\frac{n!}{k!\left(n-k\right)!} & ;0\leq k\leq n\\ +0 & ;\text{ sicer} +\end{cases} +\] + +\end_inset + + +\end_layout + +\begin_layout Proof +Dva načina. +\end_layout + +\begin_deeper +\begin_layout Enumerate +Izberemo +\begin_inset Formula $1-$ +\end_inset + +elementne podmnožice na +\begin_inset Formula $n$ +\end_inset + + načinov, + +\begin_inset Formula $2-$ +\end_inset + +elementne na +\begin_inset Formula $n-1$ +\end_inset + + načinov, + ..., + +\begin_inset Formula $k-$ +\end_inset + +elementne na +\begin_inset Formula $n-k+1$ +\end_inset + + načinov. + Delimo s številom permutacij +\begin_inset Formula $\left[k\right]$ +\end_inset + +, + ker vrstni red izbire teh podmnožic ni pomemben. + Podmnožic je torej +\begin_inset Formula $\frac{n^{\underline{k}}}{k!}$ +\end_inset + +. +\end_layout + +\begin_layout Enumerate +Preštejemo urejene izbire brez ponavljanja na dva načina: +\end_layout + +\begin_deeper +\begin_layout Enumerate +\begin_inset Formula $n^{\underline{k}}$ +\end_inset + +: + Izberemo +\begin_inset Formula $k$ +\end_inset + + elementov, + za prvega imamo +\begin_inset Formula $n$ +\end_inset + + možnosti, + za drugega +\begin_inset Formula $n-1$ +\end_inset + +, + ... +\end_layout + +\begin_layout Enumerate +\begin_inset Formula $k!\cdot\binom{n}{k}$ +\end_inset + +: + Izberemo +\begin_inset Formula $k-$ +\end_inset + +elementno podmnožico in ji določimo vrstni red. +\end_layout + +\begin_layout Standard +\begin_inset Formula +\[ +\Rightarrow n^{\underline{k}}=k!\cdot\binom{n}{k} +\] + +\end_inset + +Če +\begin_inset Formula $k<0$ +\end_inset + + ali +\begin_inset Formula $k>0$ +\end_inset + + je +\begin_inset Formula $\binom{n}{k}=0$ +\end_inset + +, + sicer +\begin_inset Formula $\frac{n^{\underline{k}}}{k!}\cdot\frac{\left(n-k\right)!}{\left(n-k\right)!}=\frac{n!}{k!\left(n-k\right)!}$ +\end_inset + +. +\end_layout + +\end_deeper +\end_deeper +\begin_layout Example* +\begin_inset Formula +\[ +\binom{10}{7}=?=\binom{10}{3}=\frac{10\cdot9\cdot8}{6}=120 +\] + +\end_inset + + +\end_layout + +\begin_layout Claim* +Rekurzivna zveza za binomske koeficiente: +\begin_inset Formula +\[ +\forall n,k\in\mathbb{N}:\binom{n}{k}=\binom{n-1}{k-1}+\binom{n-1}{k}. +\] + +\end_inset + + +\end_layout + +\begin_layout Proof +Dva načina: +\end_layout + +\begin_deeper +\begin_layout Enumerate +Računsko. +\begin_inset Formula +\[ +\binom{n-1}{k-1}+\binom{n-1}{k}=\frac{\left(n-1\right)^{\underline{k-1}}}{\left(k-1\right)!}+\frac{\left(n-1\right)^{\underline{k}}}{k!}=\frac{k\left(n-1\right)^{\underline{k-1}}+\left(n-1\right)^{\underline{k}}}{k!}=\frac{\left(n-1\right)^{\underline{k-1}}\left(\cancel{k}+n\cancel{-1}\cancel{-k}\cancel{+1}\right)}{k!}=\frac{\left(n-1\right)^{\underline{k-1}}n}{k!}=\frac{n^{\underline{k-1}}}{k!}={n \choose k} +\] + +\end_inset + + +\end_layout + +\begin_layout Enumerate +Bijektivno z načelom vsote. + Vzemimo +\begin_inset Formula $k-$ +\end_inset + +podmnožico +\begin_inset Foot +status open + +\begin_layout Plain Layout +\begin_inset Formula $k-$ +\end_inset + +elementno podmnožico +\end_layout + +\end_inset + + +\begin_inset Formula $\left[n\right]$ +\end_inset + +. + Klasificirajmo jo glede na vsebnost +\begin_inset Formula $n$ +\end_inset + + na dve očitno disjunktni podmnožici: +\end_layout + +\begin_deeper +\begin_layout Enumerate +\begin_inset Formula $n$ +\end_inset + + je element te podmnožice. + Takih je +\begin_inset Formula $\binom{n-1}{k-1}$ +\end_inset + +. +\end_layout + +\begin_layout Enumerate +\begin_inset Formula $n$ +\end_inset + + ni element te podmnožice. + Takih je +\begin_inset Formula $\binom{n-1}{k}$ +\end_inset + +. +\end_layout + +\begin_layout Standard +Formalno iščemo bijekcijo +\begin_inset Formula $\Phi:{\left[n\right] \choose k}\to\binom{\left[n-1\right]}{k-1}\cup\binom{\left[n-1\right]}{k}$ +\end_inset + +. + Predpis +\begin_inset Formula $\Phi\left(B\right)=B\setminus\left\{ n\right\} $ +\end_inset + +, + +\begin_inset Formula $\Phi^{-1}$ +\end_inset + + +\begin_inset Formula $\left(B\right)=\begin{cases} +B\cup\left\{ n\right\} & ;\left|B\right|=k-1\\ +B & ;\left|B\right|=k +\end{cases}$ +\end_inset + + +\end_layout + +\end_deeper +\end_deeper +\begin_layout Standard +Skica pascalovega trikotnika prepuščena bralcu. + TODO XXX FIXME. +\end_layout + +\begin_layout Remark* +\begin_inset Formula +\[ +\sum_{k=0}^{n}{n \choose k}=2^{n}\sim\bigcup_{k=0}^{n}{\left[n\right] \choose k}=2^{\left[n\right]}\overset{\text{disjunktne}}{\Longrightarrow}\left|\bigcup_{k=0}^{n}\binom{\left[n\right]}{k}\right|=\left|2^{\left[n\right]}\right| +\] + +\end_inset + + +\end_layout + +\begin_layout Theorem* +Binomski izrek. + Za +\begin_inset Formula $a,b$ +\end_inset + + elementa komutativnega kolobarja (polja) in za +\begin_inset Formula $n\in\mathbb{N}$ +\end_inset + + velja +\begin_inset Formula +\[ +\left(a+b\right)^{n}=\sum_{k=0}^{n}\binom{n}{k}a^{n-k}b^{k}. +\] + +\end_inset + + +\end_layout + +\begin_layout Proof +Več načinov. +\end_layout + +\begin_deeper +\begin_layout Enumerate +Induktivno. + Baza +\begin_inset Formula $n=0$ +\end_inset + +: + +\begin_inset Formula $1={0 \choose 0}a^{0}b^{0}=1$ +\end_inset + +. + Korak +\begin_inset Formula $n-1\to n$ +\end_inset + +: + +\begin_inset Formula +\[ +\left(a+b\right)^{n}\left(a+b\right)^{n-1}\left(a+b\right)\overset{\text{I.P.}}{=}\left(\sum_{k=0}^{n-1}{n-1 \choose k}a^{n-1-k}b^{k}\right)\left(a+b\right)=\sum_{k=0}^{n-1}\binom{n-1}{k}a^{n-k}b^{k}+\sum_{k=0}^{n-1}{n-1 \choose k}a^{n-1-k}b^{k+1}= +\] + +\end_inset + +... + v desni vsoti naj bo +\begin_inset Formula $k'\coloneqq k+1$ +\end_inset + + ... +\begin_inset Formula +\[ +=\sum_{k=0}^{n-1}\binom{n-1}{k}a^{n-k}b^{k}+\sum_{k'=1}^{n}\binom{n-1}{k'-1}a^{n-k'}b^{k'}= +\] + +\end_inset + +... + levo zgornjo mejo povečamo za 1, + prav tako desno spodnjo, + s čimer dodamo le dva ničelna člena. + vezano spremenljivko +\begin_inset Formula $k'$ +\end_inset + + preimenujemo v +\begin_inset Formula $k$ +\end_inset + + ... +\begin_inset Formula +\[ +=\sum_{k=0}^{n}\binom{n-1}{k}a^{n-k}b^{k}+\sum_{k=0}^{n}\binom{n-1}{k-1}a^{n-k}b^{k}=\sum_{k=0}^{n}\left[\binom{n-1}{k}+\binom{n-1}{k-1}\right]a^{n-1}b^{k}=\sum_{k=0}^{n}\binom{n}{k}a^{n-1}b^{k} +\] + +\end_inset + + +\end_layout + +\begin_layout Enumerate +Enako kot prej, + le da se ne utrujamo z mejami. + Vse meje razširimo na vsa cela števila in s tem le dodamo neskončno ničelnih členov. + Baza +\begin_inset Formula $n=0$ +\end_inset + + velja kot prej. + Korak +\begin_inset Formula $n-1\to n$ +\end_inset + +: +\begin_inset Formula +\[ +\left(a+b\right)^{n}=\left(a+b\right)^{n-1}\left(a+b\right)=\left(\sum_{k}\binom{n-1}{k}a^{n-1-k}b^{k}\right)\left(a+b\right)=\sum_{k}\binom{n-1}{k}a^{n-k}b^{k}+\sum_{k}\binom{n-1}{k}a^{n-1-k}b^{k+1}= +\] + +\end_inset + +... + zamaknemo +\begin_inset Formula $k\coloneqq k+1$ +\end_inset + + v desni vsoti ... +\begin_inset Formula +\[ +=\sum_{k}\binom{n-1}{k}a^{n-k}b^{k}+\sum_{k}\binom{n-1}{k-1}a^{n-k}b^{k}=\sum_{k}\left[\binom{n-1}{k}+\binom{n-1}{k-1}\right]a^{n-k}b^{k}=\sum_{k}\binom{n}{k}a^{n-k}b^{k} +\] + +\end_inset + + +\end_layout + +\begin_layout Enumerate +Kombinatorično. + +\begin_inset Formula $\left(a+b\right)^{n}=\left(a+b\right)\cdot\cdots\cdot\left(a+b\right)$ +\end_inset + +. + Po distributivnosti je to vsota členov, + ki so produkt enega člena iz prvega oklepaja, + enega iz drugega, + enega iz tretjega, + itd. + Če smo +\begin_inset Formula $k-$ +\end_inset + +krat izbrali +\begin_inset Formula $b$ +\end_inset + +, + smo +\begin_inset Formula $n-k-$ +\end_inset + +krat izbrali +\begin_inset Formula $a$ +\end_inset + + (skupno imamo +\begin_inset Formula $n$ +\end_inset + + izbir). + Torej je vsak člen oblike +\begin_inset Formula $a^{n-k}b^{k}$ +\end_inset + +, + +\begin_inset Formula $0\leq k\leq n$ +\end_inset + +. + Člen +\begin_inset Formula $a^{n-k}b^{k}$ +\end_inset + + dobimo na +\begin_inset Formula $\binom{n}{k}$ +\end_inset + + načinov, + ker moramo izmed +\begin_inset Formula $n$ +\end_inset + + oklepajev (faktorjev) izbrati tistih +\begin_inset Formula $k$ +\end_inset + +, + pri katerih vzamemo +\begin_inset Formula $b$ +\end_inset + +. +\end_layout + +\end_deeper +\begin_layout Corollary* +\begin_inset Formula $\left(1+x\right)^{n}=\sum_{k=0}^{n}\binom{n}{k}x^{k}$ +\end_inset + +. + Za +\begin_inset Formula $x=1$ +\end_inset + +: + +\begin_inset Formula $2^{n}=\sum_{k=0}^{n}\binom{n}{k}$ +\end_inset + +. + Za +\begin_inset Formula $x=-1$ +\end_inset + +: + +\begin_inset Formula $0^{n}=\sum_{k=0}^{n}\left(-1\right)^{k}\binom{n}{k}=\delta_{n,0}$ +\end_inset + +. +\end_layout + +\begin_layout Definition* +Kronekerjeva delta. + +\begin_inset Formula $\delta_{i,j}\coloneqq\begin{cases} +1 & ;i=j\\ +0 & ;i\not=j +\end{cases}$ +\end_inset + + +\end_layout + +\begin_layout Claim* +\begin_inset Formula $\forall n>0:\sum_{k\text{ sod}}\binom{n}{k}=\sum_{k\text{ lih}}\binom{n}{k}$ +\end_inset + + ZDB +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +hypertarget{l=s}{število lihih podmnožic} +\end_layout + +\end_inset + + neprazne končne množice +\begin_inset Formula $A$ +\end_inset + + je enako številu sodih podmnožic +\begin_inset Formula $A$ +\end_inset + +. +\end_layout + +\begin_layout Proof +Izberemo in fiksiramo element +\begin_inset Formula $u\in A$ +\end_inset + +. + Bijekcija +\begin_inset Formula $\Phi\left(B\right)=\begin{cases} +B\cup\left\{ u\right\} & ;u\not\in B\\ +B\setminus\left\{ u\right\} & ;u\in B +\end{cases}$ +\end_inset + +. +\end_layout + +\begin_layout Subsection +Izbori +\end_layout + +\begin_layout Standard +Imamo +\begin_inset Formula $n$ +\end_inset + + kroglic, + +\begin_inset Formula $k$ +\end_inset + + jih izberemo. + Vprašamo se, + ali je vrstni red pomemben in ali kroglice med izbirami vračamo v boben (nabor možnih kroglic za novo izbiro). +\end_layout + +\begin_layout Standard +\begin_inset Float table +placement document +alignment document +wide false +sideways false +status open + +\begin_layout Plain Layout +\begin_inset Tabular +<lyxtabular version="3" rows="3" columns="3"> +<features tabularvalignment="middle"> +<column alignment="center" valignment="top"> +<column alignment="center" valignment="top"> +<column alignment="center" valignment="top"> +<row> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout + +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +s ponavljanjem +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +brez ponavljanja +\end_layout + +\end_inset +</cell> +</row> +<row> +<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +vrstni red je pomemben — + variacije +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +\begin_inset Formula $n^{k}$ +\end_inset + + +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +\begin_inset Formula $n^{\underline{k}}$ +\end_inset + + +\end_layout + +\end_inset +</cell> +</row> +<row> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +vrstni red ni pomemben — + kombinacije +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +\begin_inset Formula $\binom{n+k-1}{k}$ +\end_inset + + — + +\begin_inset Formula $1\leq i_{1}\leq i_{2}\leq\cdots\leq i_{k}\leq n$ +\end_inset + + +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +\begin_inset Formula $\binom{n}{k}$ +\end_inset + + — + +\begin_inset Formula $1\leq i_{1}<i_{2}<\cdots<i_{k}\leq n$ +\end_inset + + +\end_layout + +\end_inset +</cell> +</row> +</lyxtabular> + +\end_inset + + +\end_layout + +\begin_layout Plain Layout +\begin_inset Caption Standard + +\begin_layout Plain Layout +Izbori +\end_layout + +\end_inset + + +\end_layout + +\begin_layout Plain Layout + +\end_layout + +\end_inset + + +\end_layout + +\begin_layout Proof +Kombinacij s ponavljanjem je +\begin_inset Formula $\binom{n+k-1}{k}$ +\end_inset + +. + Iščemo število rešitev sistema +\begin_inset Formula $1\leq i_{1}\leq i_{2}\leq\cdots\leq i_{k}\leq n$ +\end_inset + +. + Naj bo +\begin_inset Formula $j_{1}\coloneqq i_{1}$ +\end_inset + +, + +\begin_inset Formula $j_{2}\coloneqq i_{2}+1$ +\end_inset + +, + +\begin_inset Formula $j_{3}\coloneqq i_{3}+2$ +\end_inset + +, + +\begin_inset Formula $j_{4}\coloneqq i_{4}+3$ +\end_inset + +, + ... + +\begin_inset Formula $j_{k}\coloneqq i_{k}+k-1$ +\end_inset + +. + Dobimo sistem +\begin_inset Formula $1\leq j_{1}<j_{2}<\cdots<j_{k}\leq n+k-1$ +\end_inset + +, + ki ima enako rešitev kot prvotni sistem. + Ta sistem pa ima +\begin_inset Formula $\binom{n+k-1}{k}$ +\end_inset + + rešitev (kombinacije brez ponavljanja). +\end_layout + +\begin_layout Example* +Primer za +\begin_inset Formula $n=3$ +\end_inset + +, + +\begin_inset Formula $k=3$ +\end_inset + +: + Kombinacije s ponavljanjem: + 111, + 112, + 122, + 123, + 133, + 222, + 223, + 233, + 333. + Kombinacije brez ponavljanja za +\begin_inset Formula $n\coloneqq n+k-1=5$ +\end_inset + +, + +\begin_inset Formula $k\coloneqq k=3$ +\end_inset + +: + 123, + 124, + 134, + 135, + 145, + 234, + 235, + 245, + 345. +\end_layout + +\begin_layout Subsection +Kompozicije +\end_layout + +\begin_layout Definition* +Naj bo +\begin_inset Formula $n\in\mathbb{N}$ +\end_inset + +. + Pravimo, + da je +\begin_inset Formula $\left(\lambda_{1},\dots,\lambda_{l}\right)\in\mathbb{N}^{l}$ +\end_inset + +, + +\begin_inset Formula $\forall i\in\left[l\right]:\lambda_{i}\geq1$ +\end_inset + +, + kjer +\begin_inset Formula $\sum_{i=1}^{l}\lambda_{i}=n$ +\end_inset + +, + kompozicija števila +\begin_inset Formula $n$ +\end_inset + +. + Pravimo, + da je +\begin_inset Formula $\left(\lambda_{1},\dots,\lambda_{l}\right)\in\mathbb{N}_{0}^{l}$ +\end_inset + +, + kjer +\begin_inset Formula $\sum_{i=1}^{l}\lambda_{l}=n$ +\end_inset + +, + šibka kompozicija števila +\begin_inset Formula $n$ +\end_inset + +. + +\begin_inset Formula $\lambda_{1},\dots,\lambda_{l}$ +\end_inset + + so členi kompozicije, + +\begin_inset Formula $l$ +\end_inset + + je njena dolžina, + +\begin_inset Formula $n$ +\end_inset + + pa njena velikost. +\end_layout + +\begin_layout Example* +Vse kompozicije +\begin_inset Formula $n=3$ +\end_inset + +: + +\begin_inset Formula $\left(3\right),\left(2,1\right),\left(1,2\right),\left(1,1,1\right)$ +\end_inset + +, + kajti +\begin_inset Formula $3=3=2+1=1+2=1+1+1$ +\end_inset + +. + Ena šibka kompozicija +\begin_inset Formula $n=3$ +\end_inset + + (vseh je neskončno): + +\begin_inset Formula $\left(2,0,0,0,1,0,0,0\right)$ +\end_inset + +, + kajti +\begin_inset Formula $3=2+0+0+0+1+0+0+0$ +\end_inset + +. +\end_layout + +\begin_layout Question* +Koliko je kompozicij za dan +\begin_inset Formula $n$ +\end_inset + +? +\end_layout + +\begin_layout Theorem* +Število kompozicij +\begin_inset Formula $n=2^{n-1}$ +\end_inset + + za +\begin_inset Formula $n\geq1$ +\end_inset + +. + Število kompozicij +\begin_inset Formula $n$ +\end_inset + + dolžine +\begin_inset Formula $k={n-1 \choose k-1}$ +\end_inset + + za +\begin_inset Formula $n\geq1,k\geq1$ +\end_inset + +. +\end_layout + +\begin_layout Proof +Kompozicijo si predstavljajmo kot kroglice in pregrade: + +\begin_inset Formula $4+2+2+3+1\sim\circ\circ\circ\circ\vert\circ\circ\vert\circ\circ\vert\circ\circ\circ|\circ$ +\end_inset + +. + Kompozicija števila +\begin_inset Formula $n$ +\end_inset + +: + +\begin_inset Formula $n-1$ +\end_inset + + možnih pregrad +\begin_inset Formula $\tilde{=}$ +\end_inset + + vsi dvojiški nizi dolžine +\begin_inset Formula $n-1\Rightarrow2^{n-1}$ +\end_inset + +. + Da bo +\begin_inset Formula $k$ +\end_inset + + členov, + moramo vstaviti (izbrati mesta za) +\begin_inset Formula $k-1$ +\end_inset + + pregrad: + +\begin_inset Formula ${n-1 \choose k-1}$ +\end_inset + + možnosti. +\end_layout + +\begin_layout Theorem* +Število šibkih kompozicij +\begin_inset Formula $n\geq1$ +\end_inset + + s +\begin_inset Formula $k\geq1$ +\end_inset + + členi je +\begin_inset Formula ${n+k-1 \choose k-1}$ +\end_inset + +. +\end_layout + +\begin_layout Proof +Več načinov. +\end_layout + +\begin_deeper +\begin_layout Enumerate +Kroglice in pregrade. + Ker so členi lahko ničelni, + sta lahko tudi dve pregradi na istem mestu. + Imamo torej +\begin_inset Formula $n+k-1$ +\end_inset + + +\begin_inset Quotes gld +\end_inset + +mest +\begin_inset Quotes grd +\end_inset + +. + Na vsakem mestu je lahko bodisi kroglica bodisi pregrada. + +\begin_inset Formula $k-1$ +\end_inset + + mest za pregrade izberemo na +\begin_inset Formula $\binom{n+k-1}{k-1}$ +\end_inset + + načinov. + Kroglice so na preostalih mestih. +\end_layout + +\begin_layout Enumerate +Iščemo število rešitev enačbe +\begin_inset Formula $x_{1}+\cdots+x_{k}=n$ +\end_inset + + +\begin_inset Formula $\left(\forall i\in\left[k\right]:x_{i}\geq0\right)$ +\end_inset + +. + Vzemimo +\begin_inset Formula $\forall i\in\left[k\right]:y_{i}\coloneqq x_{i}+1$ +\end_inset + +. + Sedaj je +\begin_inset Formula $y_{i}\geq1$ +\end_inset + + in velja +\begin_inset Formula $y_{1}+\cdots+y_{k}=n+k$ +\end_inset + +. + To pa so običajne kompozicije števila +\begin_inset Formula $n+k$ +\end_inset + + s +\begin_inset Formula $k$ +\end_inset + + členi: + +\begin_inset Formula $\binom{n+k-1}{k-1}=\binom{n+k-1}{n}$ +\end_inset + + rešitev. +\end_layout + +\begin_layout Enumerate +Kombinatorično. + Opazimo podobnost formule za število šibkih kompozicij in število kombinacij s ponavljanjem? + +\begin_inset Formula $x_{i}$ +\end_inset + + ponazarja, + kolikokrat izberemo +\begin_inset Formula $i-$ +\end_inset + +to kroglico: + +\begin_inset Formula $x_{i}\in\left\{ 0..n\right\} $ +\end_inset + +. + +\begin_inset Formula $k$ +\end_inset + + predstavlja število izbranih kroglic, + +\begin_inset Formula $n$ +\end_inset + + pa število različnih kroglic. + Izmed +\begin_inset Formula $k$ +\end_inset + + različnih kroglic izberemo +\begin_inset Formula $n$ +\end_inset + + kroglic s ponavljanjem (vsako kroglico od +\begin_inset Formula $0$ +\end_inset + + do +\begin_inset Formula $n-$ +\end_inset + +krat). +\end_layout + +\end_deeper +\begin_layout Subsection +Načelo vključitev in izključitev — + NVI (angl. + principle of inclusion and exclusion — + PIE) +\end_layout + +\begin_layout Standard +\begin_inset Formula +\[ +A\cap B=\emptyset\Rightarrow\left|A\cup B\right|=\left|A\right|+\left|B\right| +\] + +\end_inset + + +\begin_inset Formula +\[ +\left|A\cup B\right|=\left|A\right|+\left|B\right|-\left|A\cap B\right| +\] + +\end_inset + + +\begin_inset Formula +\[ +\left|A\cup B\cup C\right|=\left|A\right|+\left|B\right|+\left|C\right|-\left|A\cap B\right|-\left|A\cap C\right|-\left|B\cap C\right|+\left|A\cap B\cap C\right| +\] + +\end_inset + + +\end_layout + +\begin_layout Theorem* +Naj bo +\begin_inset Formula $A_{1},\dots,A_{n}\subseteq A$ +\end_inset + + in +\begin_inset Formula $M=\left\{ A_{1},\cdots,A_{n}\right\} $ +\end_inset + +. + Za poljubno +\begin_inset Formula $I\subseteq\left[n\right]$ +\end_inset + + označimo +\begin_inset Formula $A_{I}\coloneqq\bigcap_{i\in I}A_{i}$ +\end_inset + + (npr. + +\begin_inset Formula $A_{\left\{ 2,4,8\right\} }=A_{2}\cap A_{4}\cap A_{8}$ +\end_inset + +). + Tedaj +\begin_inset Formula +\[ +\left|\bigcup_{i=1}^{n}A_{i}\right|=\left|A_{1}\right|+\cdots\left|A_{n}\right|-\left|A_{1}\cap A_{2}\right|-\cdots-\left|A_{n-1}\cap A_{n}\right|+\left|A_{1}\cap A_{2}\cap A_{3}\right|+\cdots +\] + +\end_inset + + +\begin_inset Formula +\[ +-\left|A_{1}\cap A_{2}\cap A_{3}\cap A_{4}\right|+\cdots-\cdots+\cdots+\left(-1\right)^{n+1}\left|A_{1}\cap\cdots\cap A_{n}\right|= +\] + +\end_inset + + +\begin_inset Formula +\[ +=\sum_{i=1}^{n}\left(-1\right)^{i-1}\sum_{1\leq j_{1}<\cdots<j_{i}\leq n}\left|A_{j_{1}}\cap A_{j_{2}}\cap\cdots\cap A_{j_{i}}\right|=\sum_{i=1}^{n}\left(-1\right)^{i-1}\sum_{X\in2^{M}}\left|\begin{cases} +\emptyset & ;\left|X\right|\not=i\\ +\bigcap_{Y\in X}Y & ;\text{ sicer} +\end{cases}\right|=\sum_{\emptyset\not=I\subseteq\left[n\right]}\left(-1\right)^{\left|I\right|-1}\left|A_{I}\right| +\] + +\end_inset + + +\end_layout + +\begin_layout Proof +Naj bo +\begin_inset Formula $x\in\bigcup_{i=1}^{n}A_{i}$ +\end_inset + +. + Denimo, + da je +\begin_inset Formula $x$ +\end_inset + + element natanko +\begin_inset Formula $m$ +\end_inset + + (gotovo +\begin_inset Formula $\geq1$ +\end_inset + +) množic izmed +\begin_inset Formula $A_{1},\dots,A_{n}$ +\end_inset + +. + Koliko je potem doprinos +\begin_inset Formula $x$ +\end_inset + + k vsoti na desni? + Uporabimo dejstvo, + da je +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +hyperlink{l=s}{število lihih podmnožic enako številu sodih} +\end_layout + +\end_inset + +. +\begin_inset Formula +\[ +m-{m \choose 2}+{m \choose 3}-{m \choose 4}+\cdots=\cancel{-\left(\binom{m}{0}-\binom{m}{1}+\binom{m}{2}-\binom{m}{3}+\cdots\right)}+1=1 +\] + +\end_inset + +Vsak element smo šteli natanko enkrat. +\end_layout + +\begin_layout Theorem* +NVI, + druga verzija. + +\begin_inset Formula +\[ +\left|\bigcap_{i=1}^{n}A_{i}^{\mathcal{C}}\right|=\sum_{I\subseteq\left[n\right]}\left(-1\right)^{\left|I\right|}\left|A_{I}\right| +\] + +\end_inset + + +\end_layout + +\begin_layout Proof +Pri zadnjem enačaju uporabimo dejstvo, + da je prazen produkt univerzum ( +\begin_inset Formula $A_{\emptyset}=A$ +\end_inset + +). +\begin_inset Formula +\[ +\left|\bigcap_{i=1}^{n}A_{i}^{\mathcal{C}}\right|=\left|\left(\bigcup_{i=1}^{n}A_{i}\right)^{\mathcal{C}}\right|=\left|A\right|-\left|\bigcup_{i=1}^{n}A_{i}\right|=\left|A\right|+\sum_{\emptyset\not=I\subseteq\left[n\right]}\left(-1\right)^{\left|I\right|}\left|A_{I}\right|=\sum_{I\subseteq\left[n\right]}\left(-1\right)^{\left|I\right|}\left|A_{I}\right| +\] + +\end_inset + + +\end_layout + +\begin_layout Example* +Naloge. +\end_layout + +\begin_deeper +\begin_layout Enumerate +Preštej permutacije brez negibnih točk v +\begin_inset Formula $S_{n}$ +\end_inset + +. + +\begin_inset Formula $a_{0}=1$ +\end_inset + +, + +\begin_inset Formula $a_{1}=0$ +\end_inset + +, + +\begin_inset Formula $a_{2}=1$ +\end_inset + +, + +\begin_inset Formula $a_{3}=2=\left|\left\{ \left(132\right),\left(123\right)\right\} \right|$ +\end_inset + +, + +\begin_inset Formula $a_{4}=6=\left|\left\{ \left(1234\right),\left(1243\right),\left(1324\right),\left(1342\right),\left(1423\right),\left(1432\right)\right\} \right|$ +\end_inset + +, + ... +\end_layout + +\begin_deeper +\begin_layout Standard +Naj bo +\begin_inset Formula $A\coloneqq S_{n}$ +\end_inset + +, + +\begin_inset Formula $A_{i}\coloneqq\left\{ \pi\in S_{n};\pi\left(i\right)=i\right\} $ +\end_inset + + ZDB vse permutacije, + kjer je +\begin_inset Formula $i$ +\end_inset + + negibna točka. + Iščemo torej +\begin_inset Formula $\bigcap_{i=1}^{n}A_{i}^{\mathcal{C}}=\left\{ \pi\in S_{n};\pi\text{ nima negibne točke}\right\} $ +\end_inset + +. + Izračunajmo moči presekov: +\end_layout + +\begin_layout Standard +\begin_inset Formula $\left|A_{i}\right|=\left(n-1\right)!$ +\end_inset + +, + +\begin_inset Formula $\left|A_{i}\cap A_{j}\right|=\left(n-2\right)!$ +\end_inset + +, + ..., + splošno: + +\begin_inset Formula $\left|A_{I}\right|=\left(n-\left|I\right|\right)!$ +\end_inset + + +\end_layout + +\begin_layout Standard +\begin_inset Formula +\[ +a_{n}=\sum_{I\subseteq\left[n\right]}\left(-1\right)^{\left|I\right|}\left|A_{I}\right|=\sum_{I\subseteq\left[n\right]}\left(-1\right)^{\left|I\right|}\left(n-\left|I\right|\right)!= +\] + +\end_inset + +... + imamo odvisnost le od moči +\begin_inset Formula $I$ +\end_inset + +, + ne pa tudi od vsebine +\begin_inset Formula $I$ +\end_inset + +. + Moč +\begin_inset Formula $i$ +\end_inset + + se ponovi +\begin_inset Formula ${n \choose i}-$ +\end_inset + +krat ... +\begin_inset Formula +\[ +=\sum_{i=0}^{n}\left(-1\right)^{i}\left(n-i\right)!{n \choose i}=\sum_{i=0}^{n}\left(-1\right)^{i}\cancel{\left(n-i\right)!}\frac{n!}{i!\cancel{\left(n-i\right)!}}=n!\sum_{i=0}^{n}\frac{\left(-1\right)^{i}}{i!} +\] + +\end_inset + + +\end_layout + +\end_deeper +\begin_layout Enumerate +Kakšna je verjetnost, + da je naključno izbrana permutacija brez negibne točke? +\begin_inset Formula +\[ +\lim_{n\to\infty}\frac{\cancel{n!}\sum_{i=0}^{n}\frac{\left(-1\right)^{i}}{i!}}{\cancel{n!}}=\lim_{n\to\infty}\sum_{i=0}^{n}\frac{\left(-1\right)^{i}}{i!}=e^{-1} +\] + +\end_inset + +Velja namreč +\begin_inset Formula $e^{x}=\sum_{n=0}^{\infty}\frac{x^{n}}{n!}$ +\end_inset + +. +\end_layout + +\begin_layout Enumerate +Preštej surjekcije +\begin_inset Formula $\left[n\right]\to\left[k\right]$ +\end_inset + +. +\end_layout + +\begin_deeper +\begin_layout Standard +\begin_inset Formula +\[ +A\coloneqq\left[k\right]^{\left[n\right]} +\] + +\end_inset + + +\begin_inset Formula +\[ +\forall i\in k:A_{i}\coloneqq\left\{ f:\left[n\right]\to\left[k\right];\forall i\in\left\{ 1..n\right\} :f\left(j\right)\not=i\right\} =\left\{ f:\left[n\right]\to\left[k\right]\setminus\left\{ i\right\} \right\} +\] + +\end_inset + + +\begin_inset Formula +\[ +\left|A_{i}\right|=\left(k-1\right)^{n} +\] + +\end_inset + + +\begin_inset Formula +\[ +A_{i}\cap A_{j}=\left\{ f:\left[n\right]\to\left[k\right]\setminus\left\{ i,j\right\} \right\} +\] + +\end_inset + + +\begin_inset Formula +\[ +\left|A_{i}\cap A_{j}\right|=\left(k-2\right)^{n} +\] + +\end_inset + + +\begin_inset Formula +\[ +A_{I}=\left\{ f:\left[n\right]\to\left[k\right]\setminus I\right\} +\] + +\end_inset + + +\begin_inset Formula +\[ +\left|A_{I}\right|=\left(k-\left|I\right|\right)^{n} +\] + +\end_inset + + +\begin_inset Formula +\[ +\left|\left\{ f:\left[n\right]\to\left[k\right];f\text{ surjekcija}\right\} \right|=\left|\bigcap_{i=1}^{k}A_{i}^{\mathcal{C}}\right|=\sum_{I\subseteq\left[k\right]}\left(-1\right)^{\left|I\right|}\left(k-\left|I\right|\right)^{n}=\sum_{i=0}^{k}\left(-1\right)^{i}\left(k-i\right)^{n}{k \choose i}\overset{j\coloneqq k-i}{=}\sum_{j=0}^{k}\left(-1\right)^{k-j}{k \choose j}j^{n} +\] + +\end_inset + + +\end_layout + +\end_deeper +\begin_layout Enumerate +Koliko je surjekcij v množico z 2 elementoma? + +\begin_inset Formula $k=2$ +\end_inset + +. + +\begin_inset Formula $\delta_{n,0}-2+2^{n}$ +\end_inset + +. + S tremi? + +\begin_inset Formula $k=3$ +\end_inset + +. + +\begin_inset Formula $-\delta_{n,0}+3-3\cdot2^{n}+3^{n}$ +\end_inset + + +\end_layout + +\end_deeper +\begin_layout Definition* +Eulerjeva funkcija +\begin_inset Formula $\phi$ +\end_inset + + (angl. + totient function). + +\begin_inset Formula $\phi\left(n\right)=\left|\left\{ i\in\left[n\right];\gcd\left(i,n\right)=1\right\} \right|$ +\end_inset + + ZDB št. + elementov, + ki so manjši ali enaki +\begin_inset Formula $n$ +\end_inset + + in tuji +\begin_inset Formula $n$ +\end_inset + +. +\end_layout + +\begin_layout Standard +\begin_inset Float table +placement document +alignment document +wide false +sideways false +status open + +\begin_layout Plain Layout +\begin_inset Tabular +<lyxtabular version="3" rows="2" columns="13"> +<features tabularvalignment="middle"> +<column alignment="center" valignment="top"> +<column alignment="center" valignment="top"> +<column alignment="center" valignment="top"> +<column alignment="center" valignment="top"> +<column alignment="center" valignment="top"> +<column alignment="center" valignment="top"> +<column alignment="center" valignment="top"> +<column alignment="center" valignment="top"> +<column alignment="center" valignment="top"> +<column alignment="center" valignment="top"> +<column alignment="center" valignment="top"> +<column alignment="center" valignment="top"> +<column alignment="center" valignment="top"> +<row> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +\begin_inset Formula $n$ +\end_inset + + +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +1 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +2 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +3 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +4 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +5 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +6 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +7 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +8 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +9 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +10 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +11 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +12 +\end_layout + +\end_inset +</cell> +</row> +<row> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +\begin_inset Formula $\phi\left(n\right)$ +\end_inset + + +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +1 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +1 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +2 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +2 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +4 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +2 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +6 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +4 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +6 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +4 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +10 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +4 +\end_layout + +\end_inset +</cell> +</row> +</lyxtabular> + +\end_inset + + +\end_layout + +\begin_layout Plain Layout +\begin_inset Caption Standard + +\begin_layout Plain Layout +Eulerjeva funkcija +\begin_inset Formula $\phi$ +\end_inset + + +\end_layout + +\end_inset + + +\end_layout + +\begin_layout Plain Layout + +\end_layout + +\end_inset + + +\end_layout + +\begin_layout Remark* +Za praštevilo +\begin_inset Formula $p$ +\end_inset + + velja +\begin_inset Formula $\phi\left(p\right)=p-1$ +\end_inset + +, + +\begin_inset Formula $\phi\left(p^{2}\right)=p^{2}-p$ +\end_inset + +, + +\begin_inset Formula $\phi\left(p^{k}\right)=p^{k}-p^{k-1}=p^{k}\left(1-\frac{1}{p}\right)$ +\end_inset + +. +\end_layout + +\begin_layout Claim* +\begin_inset Formula $\sum_{d\vert n}\phi\left(d\right)=n$ +\end_inset + + (vsota slik s +\begin_inset Formula $\phi$ +\end_inset + + deliteljev +\begin_inset Formula $n$ +\end_inset + + je +\begin_inset Formula $n$ +\end_inset + +). +\end_layout + +\begin_layout Proof +Oglejmo si +\begin_inset Formula $\frac{1}{n},\frac{2}{n},\frac{3}{n},\dots,\frac{n}{n}$ +\end_inset + + in okrajšajmo, + kolikor se le da. + Primer: + +\begin_inset Formula $\frac{1}{12},\frac{2}{12},\frac{3}{12},\frac{4}{12},\frac{5}{12},\frac{6}{12},\frac{7}{12},\frac{8}{12},\frac{9}{12},\frac{10}{12},\frac{11}{12},\frac{12}{12}\to\frac{1}{12},\frac{1}{6},\frac{1}{4},\frac{1}{3},\frac{5}{12},\frac{1}{2},\frac{7}{12},\frac{2}{3},\frac{3}{4},\frac{5}{6},\frac{11}{12},\frac{1}{1}$ +\end_inset + +. + Možni imenovalci so delitelji +\begin_inset Formula $n$ +\end_inset + +, + možnih števcev z imenovalcem +\begin_inset Formula $d$ +\end_inset + + pa je +\begin_inset Formula $\phi\left(d\right)$ +\end_inset + +. + Če torej grupiramo te ulomke (skupaj jih je +\begin_inset Formula $n$ +\end_inset + + — + desna stren enačbe) po imenovalcih (deliteljih), + bo pri vsakem delitelju +\begin_inset Formula $\phi\left(d\right)$ +\end_inset + + ulomkov (leva stran enačbe). +\end_layout + +\begin_layout Standard +Izrazimo +\begin_inset Formula $\phi\left(n\right)$ +\end_inset + +. + Naj bo +\begin_inset Formula $n=p_{1}^{\alpha_{1}}\cdot\cdots\cdot p_{k}^{\alpha_{k}}$ +\end_inset + + in +\begin_inset Formula $\forall i\in\left[k\right]:\alpha_{i}\geq1$ +\end_inset + +. + +\begin_inset Formula $A=\left[n\right]$ +\end_inset + +; + +\begin_inset Formula $\forall i\in\left\{ 1..k\right\} :A_{i}\coloneqq\left\{ \text{večkratniki }p_{i}\text{ v }\left[n\right]\right\} $ +\end_inset + +. + Presek komplementov so števila, + tuja +\begin_inset Formula $n$ +\end_inset + +. + +\begin_inset Formula $\left|A_{i}\right|=\left\lfloor \frac{n}{p_{i}}\right\rfloor =\frac{n}{p_{i}}$ +\end_inset + + (kajti +\begin_inset Formula $p_{i}\vert n$ +\end_inset + +), + +\begin_inset Formula $\left|A_{i}\cap A_{j}\right|=\frac{n}{p_{i}\cdot p_{j}}$ +\end_inset + +, + +\begin_inset Formula $\left|A_{I}\right|=\frac{n}{\prod_{i\in I}p_{i}}$ +\end_inset + +. +\begin_inset Formula +\[ +\phi\left(n\right)=\sum_{I\subseteq\left[k\right]}\left(-1\right)^{\left|I\right|}\frac{n}{\prod_{i\in I}p_{i}}=n\sum_{I\subseteq\left[k\right]}\left(-1\right)^{\left|I\right|}\frac{1}{\prod_{i\in I}p_{i}}=n\sum_{I\subseteq\left[k\right]}\left(-1\right)^{\left|I\right|}\prod_{i\in I}p_{i}^{-1} +\] + +\end_inset + + +\end_layout + +\begin_layout Standard +Primer za +\begin_inset Formula $k=2$ +\end_inset + + (število +\begin_inset Formula $n$ +\end_inset + + je produkt dveh praštevil): +\begin_inset Formula +\[ +\phi\left(n\right)=n\sum_{I\subseteq\left\{ 1,2\right\} }\left(-1\right)^{\left|I\right|}\prod_{i\in I}p_{i}^{-1}=n\left(1-p_{1}^{-1}-p_{2}^{-1}+p_{1}^{-1}p_{2}^{-1}\right)=n\left(1-p_{1}^{-1}\right)\left(1-p_{2}^{-1}\right) +\] + +\end_inset + + +\end_layout + +\begin_layout Standard +Primer za splošen +\begin_inset Formula $k$ +\end_inset + + (po distributivnosti): +\begin_inset Formula +\[ +\phi\left(n\right)=n\left(1-p_{1}^{-1}\right)\left(1-p_{2}^{-1}\right)\cdots\left(1-p_{k}^{-1}\right)=n\prod_{p\vert n\text{\text{ praštevilski delitelji }}}\left(1-p^{-1}\right) +\] + +\end_inset + + +\end_layout + +\begin_layout Subsection +Multinomski koeficient in multinomski izrek +\end_layout + +\begin_layout Question* +Denimo, + da imamo multimnožico (množico, + v kateri dovolimo ponavljanje elementov) +\begin_inset Formula $M\coloneqq\left\{ 1^{a_{1}},2^{a_{2}},\dots,n^{a_{n}}\right\} $ +\end_inset + + ( +\begin_inset Formula $i-$ +\end_inset + +ti element se ponovi +\begin_inset Formula $a_{i}-$ +\end_inset + +krat). + Primer: + +\begin_inset Formula $M=\left\{ 1,1,1,2,3,3\right\} =\left\{ 1^{3},2^{1},3^{2}\right\} $ +\end_inset + +. + Koliko je permutacij multimnožice? +\end_layout + +\begin_layout Standard +Naj bo +\begin_inset Formula $N=\sum_{i=1}^{n}a_{i}$ +\end_inset + +. + Enice razporedimo na +\begin_inset Formula $\binom{N}{a_{1}}$ +\end_inset + + načinov, + dvojke na +\begin_inset Formula $\binom{N-a_{1}}{a_{2}}$ +\end_inset + +, + trojke na +\begin_inset Formula $\binom{N-a_{1}-a_{2}}{a_{3}}$ +\end_inset + +, + itd. + Skupaj je permutacij torej +\begin_inset Formula +\[ +\binom{N}{a_{1}}\binom{N-a_{1}}{a_{2}}\binom{N-a_{1}-a_{2}}{a_{3}}\cdots=\frac{\left(a_{1}+\cdots+a_{n}\right)!}{a_{1}!\cancel{\left(a_{2}+\cdots+a_{n}\right)!}}\cdot\frac{\cancel{\left(a_{2}+\cdots+a_{n}\right)!}}{a_{2}!\left(a_{3}+\cdots+a_{n}\right)}\cdot\cdots=\frac{N!}{a_{1}}\cdot\frac{1}{a_{2}}\cdot\frac{1}{a_{3}}\cdot\cdots=\frac{\left(a_{1}+\cdots+a_{n}\right)!}{a_{1}!\cdot a_{2}!\cdot\cdots\cdot a_{n}!}\eqqcolon\binom{N}{a_{1},\dots,a_{n}} +\] + +\end_inset + + +\end_layout + +\begin_layout Standard +Drug način razmišljanja (intuitiven): + Ponavljajoče elemente sprva tretiramo kot različne ( +\begin_inset Formula $N!$ +\end_inset + + načinov), + nato pa delimo s fakultetami frekvenc posameznih unikatnih elementov, + saj teh elementov nočemo razlikovati. +\end_layout + +\begin_layout Remark* +\begin_inset Formula +\[ +\binom{a+b}{a,b}=\frac{\left(a+b\right)!}{a!b!}=\binom{a+b}{a}=\binom{a+b}{b} +\] + +\end_inset + + +\end_layout + +\begin_layout Theorem* +Multinomski izrek. + Kako razpisati multinom na +\begin_inset Formula $n-$ +\end_inset + +to potenco: +\begin_inset Formula +\[ +\left(x_{1}+\cdots+x_{k}\right)^{n}=\sum_{i_{1}+\cdots+i_{k}=n;i_{1},\dots,i_{k}\geq0\text{ (šibke kompozicije \ensuremath{n} dolžine \ensuremath{k})}}\binom{n}{i_{1},\dots,i_{k}}x_{1}^{i_{1}}\cdots x_{k}^{i_{k}} +\] + +\end_inset + + +\end_layout + +\begin_layout Subsection +Načrti in +\begin_inset Formula $t-$ +\end_inset + +načrti +\end_layout + +\begin_layout Definition* +\begin_inset Formula $S\subseteq X\times Y$ +\end_inset + + je relacija. + Za +\begin_inset Formula $x\in X$ +\end_inset + + in +\begin_inset Formula $y\in Y$ +\end_inset + + velja +\begin_inset Formula $xSy\Leftrightarrow\left(x,y\right)\in S$ +\end_inset + +. + Za +\begin_inset Formula $x\in X$ +\end_inset + + označimo +\begin_inset Formula $v_{x}\left(S\right)\coloneqq\left|\left\{ y\in Y;xSy\right\} \right|$ +\end_inset + + (število kljukic v vrstici +\begin_inset Formula $x$ +\end_inset + +). + Za +\begin_inset Formula $y\in Y$ +\end_inset + + označimo +\begin_inset Formula $s_{y}\left(S\right)\coloneqq\left|\left\{ x\in X;xSy\right\} \right|$ +\end_inset + + (število kljukic v stolpcu +\begin_inset Formula $y$ +\end_inset + +). +\end_layout + +\begin_layout Definition* +Velja +\begin_inset Formula $\left|S\right|=\sum_{x\in X}v_{x}\left(S\right)=\sum_{y\in Y}s_{y}\left(S\right)$ +\end_inset + +. + Kdaj se zgodi, + da je +\begin_inset Formula $\forall x,x'\in X:v_{x}\left(S\right)=v_{x'}\left(S\right)$ +\end_inset + +, + tedaj označimo kar +\begin_inset Formula $v\left(S\right)$ +\end_inset + + in analogno za +\begin_inset Formula $s\left(x\right)$ +\end_inset + + in tedaj velja +\begin_inset Formula $\sum_{x\in X}v_{x}\left(S\right)=v\left(s\right)\left|X\right|$ +\end_inset + +. + Če to velja za stolpce in vrstice, + velja +\begin_inset Formula $v\left(S\right)\cdot\left|X\right|=s\left(S\right)\cdot\left|Y\right|$ +\end_inset + +. +\end_layout + +\begin_layout Example* +Dva primera. +\end_layout + +\begin_deeper +\begin_layout Enumerate +Trianguilacija ravninskega grafa je ravninski graf in zanjo velja, + da so vsa lica +\begin_inset Formula $3-$ +\end_inset + +cikli. + Za vsak ravninski graf je moč najti triangulacijo ravninskega grafa. + Naj bo +\begin_inset Formula $G$ +\end_inset + + triangulacija ravninskega grafa. + Za relacijo +\begin_inset Formula $S=EG\times FG$ +\end_inset + + s predpisom +\begin_inset Formula $eSf\Leftrightarrow e\in f$ +\end_inset + + velja +\begin_inset Formula $\forall e,e'\in EG:v_{e}\left(S\right)=v_{e'}\left(S\right)=2$ +\end_inset + + in +\begin_inset Formula $\forall f,f'\in FG:s_{f}\left(S\right)=s_{f'}\left(S\right)=3$ +\end_inset + +. + Torej +\begin_inset Formula $v\left(S\right)=2$ +\end_inset + + in +\begin_inset Formula $s\left(S\right)=3$ +\end_inset + +, + sledi +\begin_inset Formula $3\left|F\right|=2\left|E\right|$ +\end_inset + +. +\end_layout + +\begin_layout Enumerate +Koliko deliteljev ima v povprečju število +\begin_inset Formula $n$ +\end_inset + +? + Naj bo +\begin_inset Formula $S=\left[n\right]\times\left[n\right]$ +\end_inset + + s predpisom +\begin_inset Formula $xSy\Leftrightarrow x\vert y$ +\end_inset + +. + Velja +\begin_inset Formula $s_{y}\left(S\right)=$ +\end_inset + + število deliteljev +\begin_inset Formula $y$ +\end_inset + + in +\begin_inset Formula $v_{x}\left(S\right)=\left\lfloor \frac{n}{x}\right\rfloor $ +\end_inset + +. + +\begin_inset Formula $\sum_{i=1}^{n}\left\lfloor \frac{n}{i}\right\rfloor =\sum_{j=1}^{n}$ +\end_inset + +št. + del. + +\begin_inset Formula $j$ +\end_inset + +. + Koliko je povprečje? +\begin_inset Formula +\[ +\frac{1}{n}\sum_{j=1}^{n}\text{\#del.}j\overset{\text{asimptotsko enako}}{\sim}\frac{1}{\cancel{n}}\sum_{j=1}\frac{\cancel{n}}{i}=\sum_{j=1}^{1}\frac{1}{i}=H_{n}=n-\text{to harmonično število} +\] + +\end_inset + + +\begin_inset Formula +\[ +\lim_{n\to\infty}H_{n}=\ln\left(n\right) +\] + +\end_inset + + +\end_layout + +\end_deeper +\begin_layout Paragraph* +Motivacija za načrte +\end_layout + +\begin_layout Standard +Podjetje ima izdelek v več različicah in ga testira na več potrošnikih. + Zahteve: +\end_layout + +\begin_layout Enumerate +hočemo, + da vsak potrošnik testira enako različic. +\end_layout + +\begin_layout Enumerate +hočemo, + da je vsaka različica enakokrat testirana. +\end_layout + +\begin_layout Standard +Temu pravimo načrt. + Sledi formalnejša definicija, + kjer je število potrošnikov +\begin_inset Formula $b$ +\end_inset + +, + število različic +\begin_inset Formula $v$ +\end_inset + +, + +\begin_inset Formula $k$ +\end_inset + + število različic na potrošnika, + +\begin_inset Formula $\lambda$ +\end_inset + + pa število potrošnikov na različico. +\end_layout + +\begin_layout Definition* +\begin_inset Formula $B=\left\{ B_{1},\dots,B_{b}\right\} $ +\end_inset + + je načrt s parametri +\begin_inset Formula $\left(v,k,\lambda\right)$ +\end_inset + +, + če velja +\begin_inset Formula $B_{1},\dots,B_{b}\subseteq\left[v\right]$ +\end_inset + +, + +\begin_inset Formula $\forall i\in\left[b\right]:\left|B_{i}\right|=k$ +\end_inset + +, + +\begin_inset Formula $\forall i\in\left[v\right]\exists$ +\end_inset + + natanko +\begin_inset Formula $\lambda$ +\end_inset + + množic, + v katerih je +\begin_inset Formula $i$ +\end_inset + + vsebovan. +\end_layout + +\begin_layout Definition* +Če si predstavljamo relacijo +\begin_inset Formula $S\subseteq\left[v\right]\times B$ +\end_inset + + s predpisom +\begin_inset Formula $iSB_{j}\Leftrightarrow i\in B_{j}$ +\end_inset + +, + zanjo velja +\begin_inset Formula $v\left(S\right)=\lambda$ +\end_inset + + in +\begin_inset Formula $s\left(S\right)=k$ +\end_inset + +, + torej +\begin_inset Formula $v\cdot\lambda=k\cdot b$ +\end_inset + +. +\end_layout + +\begin_layout Remark* +Potreben pogoj za načrt je, + da je +\begin_inset Formula $v\cdot\lambda=k\cdot b$ +\end_inset + +, + da +\begin_inset Formula $k\vert v\cdot\lambda$ +\end_inset + + in da +\begin_inset Formula $b\leq{v \choose k}\Longrightarrow\frac{v\lambda}{k}\leq{v \choose k}\Rightarrow\lambda\leq\frac{\cancel{k}\cancelto{\left(v-1\right)!}{v!}}{\cancelto{\left(k-1\right)!}{k!}\cancel{v}\left(v-k\right)!}={v-1 \choose k-1}$ +\end_inset + + (število +\begin_inset Formula $k-$ +\end_inset + +elementnih podmnožic +\begin_inset Formula $\left[v\right]$ +\end_inset + +, + ki vsebujejo +\begin_inset Formula $i$ +\end_inset + +) +\end_layout + +\begin_layout Theorem* +Načrt s parametri +\begin_inset Formula $\left(v,k,\lambda\right)\exists\Leftrightarrow\lambda\leq{v-1 \choose k-1}\wedge k\vert v\lambda$ +\end_inset + +. +\end_layout + +\begin_layout Proof +Dokazujemo ekvivalenco. +\end_layout + +\begin_deeper +\begin_layout Labeling +\labelwidthstring 00.00.0000 +\begin_inset Formula $\left(\Rightarrow\right)$ +\end_inset + + Že dokazano v zgornji opombi (potreben pogoj). +\end_layout + +\begin_layout Labeling +\labelwidthstring 00.00.0000 +\begin_inset Formula $\left(\Leftarrow\right)$ +\end_inset + + Po predpostavki +\begin_inset Formula $\lambda\leq{v-1 \choose k-1}\wedge k\vert v\lambda$ +\end_inset + +. + Npr. + +\begin_inset Formula $v=8,k=4,\lambda=3$ +\end_inset + + ustreza +\begin_inset Formula $4\vert8\cdot3$ +\end_inset + + in +\begin_inset Formula $3\leq{7 \choose 3}=35$ +\end_inset + +. +\end_layout + +\begin_deeper +\begin_layout Standard +Izberimo poljubnih +\begin_inset Formula $b$ +\end_inset + + različnih +\begin_inset Formula $k-$ +\end_inset + +podmnožic +\begin_inset Formula $\left[v\right]$ +\end_inset + +. + To lahko storimo, + ker je +\begin_inset Formula $b=\frac{v\lambda}{k}\leq\frac{v}{k}{v-1 \choose k-1}={v \choose k}$ +\end_inset + +. +\end_layout + +\begin_layout Standard +Vzamemo npr. + 1234, + 1356, + 1567, + 1568, + 2356, + 3457. + Z +\begin_inset Formula $\lambda_{i}$ +\end_inset + + označimo, + v koliko blokih je +\begin_inset Formula $i$ +\end_inset + +. + Tedaj +\begin_inset Formula $\lambda_{1}=4$ +\end_inset + +, + +\begin_inset Formula $\lambda_{2}=2$ +\end_inset + +, + +\begin_inset Formula $\lambda_{3}=4$ +\end_inset + +, + +\begin_inset Formula $\lambda_{4}=2$ +\end_inset + +, + +\begin_inset Formula $\lambda_{5}=5$ +\end_inset + +, + +\begin_inset Formula $\lambda_{6}=4$ +\end_inset + +, + +\begin_inset Formula $\lambda_{7}=2$ +\end_inset + +, + +\begin_inset Formula $\lambda_{8}=1$ +\end_inset + +. + To ni načrt. +\end_layout + +\begin_layout Standard +\begin_inset Formula $k$ +\end_inset + + kljukic že je v vsakem stolpcu, + a v vsaki vrstici ni enako kljukic (v +\begin_inset Formula $i-$ +\end_inset + +ti jih je +\begin_inset Formula $\lambda_{i}$ +\end_inset + +). + Velja +\begin_inset Formula $\sum_{i=1}^{v}\lambda_{i}=k\cdot b=\lambda v\Longrightarrow\frac{\sum_{i=1}^{v}\lambda_{i}}{v}=\overline{\lambda_{i}}=\lambda$ +\end_inset + +. + Če +\begin_inset Formula $\forall i\in\left[v\right]:\lambda_{i}=\lambda$ +\end_inset + +, + imamo načrt in smo končali, + sicer vzamemo +\begin_inset Formula $i$ +\end_inset + + in +\begin_inset Formula $j$ +\end_inset + +, + da +\begin_inset Formula $\lambda_{i}<\lambda<\lambda_{j}$ +\end_inset + + (gotovo +\begin_inset Formula $\exists$ +\end_inset + + zaradi prejšnjega razmisleka o povprečju). +\end_layout + +\begin_layout Standard +Bloki so štirih disjunktnih tipov: + +\begin_inset Formula $I:i,j\in B$ +\end_inset + +, + +\begin_inset Formula $II:i\not\in B,j\in B$ +\end_inset + +, + +\begin_inset Formula $III:i\in B,j\not\in B$ +\end_inset + +, + +\begin_inset Formula $IV:i\not\in B,j\not\in B$ +\end_inset + +. + Velja +\begin_inset Formula $\lambda_{i}=\left|I\right|+\left|III\right|$ +\end_inset + +, + +\begin_inset Formula $\lambda_{j}=\left|I\right|+\left|II\right|$ +\end_inset + +. + Vemo +\begin_inset Formula $\lambda_{i}<\lambda_{j}\Rightarrow\left|III\right|<\left|II\right|\Rightarrow$ +\end_inset + + gotovo +\begin_inset Formula $\exists$ +\end_inset + + vsak en blok tipa +\begin_inset Formula $II$ +\end_inset + +. +\end_layout + +\begin_layout Standard +Treba je še dokazati, + da obstaja blok tipa +\begin_inset Formula $II$ +\end_inset + +, + kjer pri menjavi elementa +\begin_inset Formula $j$ +\end_inset + + z elementom +\begin_inset Formula $i$ +\end_inset + + dobimo blok, + ki še ne obstaja. + Vemo, + da je blokov tipa +\begin_inset Formula $II$ +\end_inset + + gotovo več od blokov tipa +\begin_inset Formula $III$ +\end_inset + +. + Po naši menjavi dobimo iz bloka +\begin_inset Formula $II$ +\end_inset + + blok +\begin_inset Formula $III$ +\end_inset + +. + Ker je blokov tipa +\begin_inset Formula $II$ +\end_inset + + več od blokov tipa +\begin_inset Formula $III$ +\end_inset + +, + +\begin_inset Formula $\exists$ +\end_inset + + blok tipa +\begin_inset Formula $II$ +\end_inset + +, + da ob menjavi dobimo nov blok tipa +\begin_inset Formula $III$ +\end_inset + +, + ki še ni med poprejšnjimi bloki — + je nov. +\end_layout + +\begin_layout Standard +Zakaj se algoritem ustavi? + +\begin_inset Formula $\sum_{i=1}^{v}\left|\lambda_{i}-\lambda\right|$ +\end_inset + + je na vsakem koraku za 2 manjša. + Ko je vsota enaka 1 (nedosegljivo stanje, + kajti tedaj +\begin_inset Formula $\overline{\lambda_{i}}\not=\lambda$ +\end_inset + +) ali 0, + se ustavimo in imamo načrt. +\end_layout + +\end_deeper +\end_deeper +\begin_layout Definition* +\begin_inset Formula $t-$ +\end_inset + +načrt. + +\begin_inset Formula $B=\left\{ B_{1},\dots,B_{b}\right\} $ +\end_inset + + je +\begin_inset Formula $t-$ +\end_inset + +načrt s parametri +\begin_inset Formula $\left(v,k,\lambda_{t}\right),$ +\end_inset + +če se ne le vsak element pojavi +\begin_inset Formula $t-$ +\end_inset + +krat, + temveč se celo vsaka +\begin_inset Formula $t-$ +\end_inset + +elementna podmnožica +\begin_inset Formula $\left[v\right]$ +\end_inset + + pojavi natanko +\begin_inset Formula $t-$ +\end_inset + +krat ZDB +\begin_inset Formula $B$ +\end_inset + + je načrt in +\begin_inset Formula $\forall A\subseteq\left[v\right]:A\subseteq B_{j}$ +\end_inset + + za natanko +\begin_inset Formula $\lambda_{t}$ +\end_inset + + indeksov +\begin_inset Formula $j$ +\end_inset + +. +\end_layout + +\begin_layout Remark* +Načrt je isto kot +\begin_inset Formula $1-$ +\end_inset + +načrt. + +\begin_inset Formula $t-$ +\end_inset + +načrt je posplošitev načrta. +\end_layout + +\begin_layout Example* +Primeri. +\end_layout + +\begin_deeper +\begin_layout Enumerate +Fanova ravnina. +\end_layout + +\begin_deeper +\begin_layout Standard +\begin_inset Float figure +placement document +alignment document +wide false +sideways false +status open + +\begin_layout Plain Layout +\begin_inset Graphics + filename fanova_ravnina.png + +\end_inset + + +\end_layout + +\begin_layout Plain Layout +\begin_inset Caption Standard + +\begin_layout Plain Layout +Fanova ravnina z +\begin_inset Formula $v=7$ +\end_inset + + +\end_layout + +\end_inset + + +\end_layout + +\begin_layout Plain Layout + +\end_layout + +\end_inset + +Zapiši vse točke, + ki ležijo na isti premici, + kjer je rumen krog tudi premica. + 123, + 156, + 147, + 257, + 345, + 362, + 264. + To je načrt in hkrati +\begin_inset Formula $2-$ +\end_inset + +načrt s parametri +\begin_inset Formula $v=7$ +\end_inset + +, + +\begin_inset Formula $k=3$ +\end_inset + +, + +\begin_inset Formula $\lambda_{1}=3$ +\end_inset + +, + +\begin_inset Formula $\lambda_{2}=1$ +\end_inset + +. +\end_layout + +\end_deeper +\begin_layout Enumerate +\begin_inset Formula $3-$ +\end_inset + +načrt s parametri +\begin_inset Formula $\left(8,4,1\right)$ +\end_inset + +: + 1235, + 1248, + 1267, + 1346, + 1378, + 1457, + 1568, + 2347, + 2368, + 2456, + 2578, + 3458, + 3567, + 4678. +\end_layout + +\end_deeper +\begin_layout Theorem* +Če je +\begin_inset Formula $B$ +\end_inset + + +\begin_inset Formula $t-$ +\end_inset + +načrt s parametri +\begin_inset Formula $\left(v,k,\lambda_{t}\right)$ +\end_inset + +, + je tudi +\begin_inset Formula $\left(t-1\right)-$ +\end_inset + +načrt s paramatri +\begin_inset Formula $\left(v,k,\lambda_{t-1}\right)$ +\end_inset + +, + kjer je +\begin_inset Formula $\lambda_{t-1}=\frac{v-\left(t-1\right)}{k-\left(t-1\right)}$ +\end_inset + +. +\end_layout + +\begin_layout Proof +Naj bo +\begin_inset Formula $S\subseteq\left[v\right],\left|S\right|=t-1$ +\end_inset + +, + +\begin_inset Formula $\lambda_{S}\coloneqq$ +\end_inset + + v koliko blokih je +\begin_inset Formula $S$ +\end_inset + + vsebovana. + Naj bo +\begin_inset Formula $R\subseteq\left[v\right]\times B$ +\end_inset + + relacija s predpisom +\begin_inset Formula $iRB_{j}\Leftrightarrow i\not\in S\wedge S\cup\left\{ i\right\} \subseteq B_{j}$ +\end_inset + +. + V vrstici je za dani +\begin_inset Formula $i$ +\end_inset + + 0 kljukic, + če +\begin_inset Formula $i\in S$ +\end_inset + +, + sicer (če +\begin_inset Formula $i\not\in S$ +\end_inset + +) pa +\begin_inset Formula $\lambda_{t}$ +\end_inset + + kljukic. + V stolpcu je za dani +\begin_inset Formula $B_{j}$ +\end_inset + + 0 kljukic, + če +\begin_inset Formula $S\not\subseteq B_{j}$ +\end_inset + +, + sicer (če +\begin_inset Formula $S\subseteq B$ +\end_inset + +), + pa +\begin_inset Formula $k-\left(t-1\right)$ +\end_inset + + kljukic. + Pomaga skica tabele +\begin_inset Formula $R$ +\end_inset + +. + V +\begin_inset Formula $v-\left(t-1\right)$ +\end_inset + + vrsticah se zgodi, + da +\begin_inset Formula $i\not\in S$ +\end_inset + +. + Preštejmo po vrsticah in nato po stolpcih: +\begin_inset Formula +\[ +\left(v-\left(t-1\right)\right)\lambda_{t}=\lambda_{s}\left(k-\left(t-1\right)\right) +\] + +\end_inset + + +\begin_inset Formula +\[ +\lambda_{s}=\frac{\left(v-\left(t-1\right)\right)\lambda_{t}}{k-\left(t-1\right)} +\] + +\end_inset + + +\begin_inset Formula +\[ +\lambda_{t-1}\coloneqq\lambda_{s} +\] + +\end_inset + + +\end_layout + +\begin_layout Section +Permutacije, + razdelitve, + razčlenitve +\end_layout + +\begin_layout Subsection +Stirlingova števila 1. + vrste +\end_layout + +\begin_layout Definition* +\begin_inset Formula $c\left(n,k\right)=$ +\end_inset + + število permutacij +\begin_inset Formula $n$ +\end_inset + + elementov, + ki imajo +\begin_inset Formula $k$ +\end_inset + + ciklov. +\end_layout + +\begin_layout Example* +\begin_inset Formula $c\left(3,1\right)=2$ +\end_inset + +, + +\begin_inset Formula $c\left(3,2\right)=3$ +\end_inset + +, + +\begin_inset Formula $c\left(3,3\right)=1$ +\end_inset + +, + +\begin_inset Formula $c\left(4,2\right)=4\cdot2+3=11$ +\end_inset + +, + +\begin_inset Formula $c\left(n,n\right)=1$ +\end_inset + +, + +\begin_inset Formula $c\left(n,n-1\right)={n \choose 2}$ +\end_inset + +, + +\begin_inset Formula $c\left(n,1\right)=\left(n-1\right)!$ +\end_inset + +, + +\begin_inset Formula $c\left(n,n\right)=\delta_{0,n}$ +\end_inset + +, + +\begin_inset Formula $\sum_{k}c\left(n,k\right)=n!$ +\end_inset + + (vse permutacije +\begin_inset Formula $n$ +\end_inset + + elementov). +\end_layout + +\begin_layout Claim* +\begin_inset Formula $c\left(n,k\right)=c\left(n-1,k-1\right)+c\left(n-1,k\right)\cdot\left(n-1\right)$ +\end_inset + + +\end_layout + +\begin_layout Proof +Permutacije v +\begin_inset Formula $S_{n}$ +\end_inset + + s +\begin_inset Formula $k$ +\end_inset + + cikli ločimo na: +\end_layout + +\begin_deeper +\begin_layout Itemize +take, + ki vsebujejo cikel +\begin_inset Formula $\left(n\right)$ +\end_inset + + ( +\begin_inset Formula $n$ +\end_inset + + je negibna točka): + teh je +\begin_inset Formula $c\left(n-1,k-1\right)$ +\end_inset + + +\end_layout + +\begin_layout Itemize +take, + ki ne vsebujejo cikla +\begin_inset Formula $\left(n\right)$ +\end_inset + +: + teh je +\begin_inset Formula $c\left(n-1,k\right)\cdot\left(n-1\right)$ +\end_inset + +. + Če +\begin_inset Formula $n$ +\end_inset + + odstranimo, + se število ciklov ne spremeni, + vendar ga ne moremo vstaviti nazaj enolično, + temveč na +\begin_inset Formula $n-1$ +\end_inset + + načinov. +\end_layout + +\end_deeper +\begin_layout Proof +\begin_inset Float table +placement document +alignment document +wide false +sideways false +status open + +\begin_layout Plain Layout +\begin_inset Tabular +<lyxtabular version="3" rows="7" columns="7"> +<features tabularvalignment="middle"> +<column alignment="center" valignment="top"> +<column alignment="center" valignment="top"> +<column alignment="center" valignment="top"> +<column alignment="center" valignment="top"> +<column alignment="center" valignment="top"> +<column alignment="center" valignment="top"> +<column alignment="center" valignment="top"> +<row> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +n +\backslash +k +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +1 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +2 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +3 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +4 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +5 +\end_layout + +\end_inset +</cell> +</row> +<row> +<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +1 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +</row> +<row> +<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +1 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +1 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +</row> +<row> +<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +2 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +1 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +1 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +</row> +<row> +<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +3 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +2 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +3 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +1 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +</row> +<row> +<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +4 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +6 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +11 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +6 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +1 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +</row> +<row> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +5 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +24 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +50 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +35 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +10 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +1 +\end_layout + +\end_inset +</cell> +</row> +</lyxtabular> + +\end_inset + + +\end_layout + +\begin_layout Plain Layout +\begin_inset Caption Standard + +\begin_layout Plain Layout +Tabela stirlingovih števil. +\end_layout + +\end_inset + + +\end_layout + +\end_inset + + +\end_layout + +\begin_layout Theorem* +\begin_inset Formula $\sum_{k=0}^{n}c\left(n,k\right)x^{k}=x^{\overline{n}}$ +\end_inset + + +\end_layout + +\begin_layout Example* +\begin_inset Formula $n=3$ +\end_inset + +: + +\begin_inset Formula $2x^{1}+3x^{2}+1x^{2}=x\left(x^{2}+3x+2\right)=x\left(x+1\right)\left(x+2\right)$ +\end_inset + + +\end_layout + +\begin_layout Proof +Indukcija po +\begin_inset Formula $n\in\mathbb{N}_{0}$ +\end_inset + +. + Baza +\begin_inset Formula $n=0$ +\end_inset + +: + +\begin_inset Formula $1=1$ +\end_inset + +. + Korak +\begin_inset Formula $n-1\to n$ +\end_inset + +: +\begin_inset Formula +\[ +x^{\overline{n}}=x^{\overline{n-1}}\left(x+n-1\right)\overset{\text{I. P.}}{=}\sum_{k=0}^{n-1}c\left(n-1,k\right)x^{k}\left(x+n-1\right)=\sum_{k}c\left(n-1,k\right)x^{k+1}+\sum_{k}\left(n-1\right)c\left(n-1,k\right)x^{k}= +\] + +\end_inset + + +\begin_inset Formula +\[ +=\sum_{k}c\left(n-1,k-1\right)x^{k}+\sum_{k}\left(n-1\right)c\left(n-1,k\right)x^{k}=\sum_{k}\left(c\left(n-1,k-1\right)+\left(n-1\right)c\left(n-1,k\right)\right)x^{k}=\sum_{k}c\left(n,k\right)x^{k} +\] + +\end_inset + + +\end_layout + +\begin_layout Example* +\begin_inset Formula $x=1$ +\end_inset + +: + število permutacij z vsemi števili ciklov +\begin_inset Formula $=\sum_{k}c\left(n,k\right)=x^{\overline{n}}=1^{\overline{n}}=n!=$ +\end_inset + + vse permutacije. +\end_layout + +\begin_layout Subsection +Stirlingova števila 2. + vrste in Bellova števila +\end_layout + +\begin_layout Definition* +Razdelitev ali razbitje (ali particija) (angl. + set partition) množice +\begin_inset Formula $A$ +\end_inset + + je množica množic (pravimo jim bloki) +\begin_inset Formula $\left\{ B_{1},\dots,B_{k}\right\} $ +\end_inset + +, + da velja: +\end_layout + +\begin_deeper +\begin_layout Itemize +\begin_inset Formula $\forall i\in\left[k\right]:B_{i}\not=\emptyset$ +\end_inset + + +\end_layout + +\begin_layout Itemize +\begin_inset Formula $\forall i,k\in\left[k\right]:i\not=j\Rightarrow B_{i}\cap B_{j}=\emptyset$ +\end_inset + + +\end_layout + +\begin_layout Itemize +\begin_inset Formula $\bigcup_{i=1}^{k}B_{i}=A$ +\end_inset + + +\end_layout + +\end_deeper +\begin_layout Standard +\begin_inset Separator plain +\end_inset + + +\end_layout + +\begin_layout Definition* +Stirlingovo število druge vrste +\begin_inset Formula $S\left(n,k\right)$ +\end_inset + + je število razdelitev množice +\begin_inset Formula $\left[n\right]$ +\end_inset + + s +\begin_inset Formula $k$ +\end_inset + + bloki. + Bellovo število +\begin_inset Formula $B\left(n\right)$ +\end_inset + + je število vseh razdelive +\begin_inset Formula $\left[n\right]$ +\end_inset + +. +\end_layout + +\begin_layout Example* +\begin_inset Formula $S\left(4,2\right)=7$ +\end_inset + +; + +\begin_inset Formula $\left\{ 1,2,3,4\right\} $ +\end_inset + + razdelimo na +\begin_inset Formula $\left\{ \left\{ \_\right\} ,\left\{ \_,\_,\_\right\} \right\} $ +\end_inset + + +\begin_inset Formula $\times4$ +\end_inset + +, + +\begin_inset Formula $\left\{ \left\{ \_,\_\right\} ,\left\{ \_,\_\right\} \right\} $ +\end_inset + + +\begin_inset Formula $\times3$ +\end_inset + + (fiksiramo enko v prvi blok, + imamo še tri izbire za njeno sosedo, + v drugem bloku so nato enolično določeni elementi) +\end_layout + +\begin_layout Standard +\begin_inset Float table +placement document +alignment document +wide false +sideways false +status open + +\begin_layout Plain Layout +\begin_inset Tabular +<lyxtabular version="3" rows="5" columns="2"> +<features tabularvalignment="middle"> +<column alignment="center" valignment="top"> +<column alignment="center" valignment="top"> +<row> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +\begin_inset Formula $n$ +\end_inset + + +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +\begin_inset Formula $B\left(n\right)$ +\end_inset + + +\end_layout + +\end_inset +</cell> +</row> +<row> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +1 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +1 +\end_layout + +\end_inset +</cell> +</row> +<row> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +2 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +2 +\end_layout + +\end_inset +</cell> +</row> +<row> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +3 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +5 +\end_layout + +\end_inset +</cell> +</row> +<row> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +4 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +\begin_inset Formula $S\left(4,1\right)+S\left(4,2\right)+S\left(4,3\right)+S\left(4,4\right)=1+7+6+1=15$ +\end_inset + + +\end_layout + +\end_inset +</cell> +</row> +</lyxtabular> + +\end_inset + + +\end_layout + +\begin_layout Plain Layout +\begin_inset Caption Standard + +\begin_layout Plain Layout +Bellova števila +\end_layout + +\end_inset + + +\end_layout + +\begin_layout Plain Layout + +\end_layout + +\end_inset + + +\end_layout + +\begin_layout Remark* +\begin_inset Formula $S\left(n,0\right)=\delta_{0,n}$ +\end_inset + +, + +\begin_inset Formula $S\left(n,n\right)=1$ +\end_inset + +, + +\begin_inset Formula $B\left(n\right)=\sum_{k}S\left(n,k\right)$ +\end_inset + +, + +\begin_inset Formula $S\left(n,n-1\right)={n \choose 2}$ +\end_inset + + +\end_layout + +\begin_layout Claim* +Rekurzivna zveza. + +\begin_inset Formula $S\left(n,k\right)=S\left(n-1,k-1\right)+k\cdot S\left(n-1,k\right)$ +\end_inset + +, + +\begin_inset Formula $B\left(n+1\right)=\sum_{k=0}^{n}{n \choose k}B\left(k\right)$ +\end_inset + + +\end_layout + +\begin_layout Example* +\begin_inset Formula $B\left(4\right)={3 \choose 0}B\left(0\right)+{3 \choose 1}B\left(1\right)+{3 \choose 2}B\left(2\right)+{3 \choose 3}B\left(3\right)=1\cdot1+3\cdot1+3\cdot2+1\cdot5=15$ +\end_inset + + +\end_layout + +\begin_layout Proof +Ločimo vse razdelitve +\begin_inset Formula $\left[n\right]$ +\end_inset + + s +\begin_inset Formula $k$ +\end_inset + + bloki na dve disjunktni podmnožici: +\end_layout + +\begin_deeper +\begin_layout Itemize +\begin_inset Formula $\left\{ n\right\} $ +\end_inset + + je blok: + takih je +\begin_inset Formula $S\left(n-1,k-1\right)$ +\end_inset + + +\end_layout + +\begin_layout Itemize +\begin_inset Formula $\left\{ n\right\} $ +\end_inset + + ni blok: + takih je +\begin_inset Formula $S\left(n-1,k\right)\cdot k$ +\end_inset + + — + +\begin_inset Formula $\cdot k$ +\end_inset + + ker lahko v razdelitev +\begin_inset Formula $\left[n-1\right]$ +\end_inset + + na +\begin_inset Formula $k$ +\end_inset + + blokov +\begin_inset Formula $n$ +\end_inset + + vstavimo na +\begin_inset Formula $k$ +\end_inset + + načinov (v enega izmed +\begin_inset Formula $k$ +\end_inset + + blokov) +\end_layout + +\begin_layout Standard +Vse razdelitve +\begin_inset Formula $\left[n+1\right]$ +\end_inset + + — + Bellova števila: + Naj bo +\begin_inset Formula $n+1$ +\end_inset + + v bloku s še +\begin_inset Formula $k$ +\end_inset + + elementi, + +\begin_inset Formula $0\leq k\leq n$ +\end_inset + +. + Tedaj +\begin_inset Formula +\[ +B\left(n+1\right)=\sum_{k=0}^{n}{n \choose k}B\left(n+1-k-1\right)= +\] + +\end_inset + +... + za rekurzijo si oglejmo razdelitve brez bloka z +\begin_inset Formula $n+1$ +\end_inset + +. + +\begin_inset Formula ${n \choose k}$ +\end_inset + + predstavlja izbiro elementov, + ki so še skupaj z +\begin_inset Formula $n$ +\end_inset + + ... +\begin_inset Formula +\[ +=\sum_{k=0}^{n}{n \choose k}B\left(n-k\right)\overset{\text{štejmo v drugo smer}}{=}\sum_{k=0}^{n}{n \choose n-k}B\left(k\right)=\sum_{k=0}^{n}{n \choose k}B\left(k\right) +\] + +\end_inset + + +\end_layout + +\end_deeper +\begin_layout Proof +\begin_inset Float table +placement document +alignment document +wide false +sideways false +status open + +\begin_layout Plain Layout +\begin_inset Tabular +<lyxtabular version="3" rows="7" columns="8"> +<features tabularvalignment="middle"> +<column alignment="center" valignment="top"> +<column alignment="center" valignment="top"> +<column alignment="center" valignment="top"> +<column alignment="center" valignment="top"> +<column alignment="center" valignment="top"> +<column alignment="center" valignment="top"> +<column alignment="center" valignment="top"> +<column alignment="center" valignment="top"> +<row> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +\begin_inset Formula $n\backslash k$ +\end_inset + + +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +1 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +2 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +3 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +4 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +5 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +\begin_inset Formula $B\left(n\right)$ +\end_inset + + (vsota po vrstici) +\end_layout + +\end_inset +</cell> +</row> +<row> +<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +1 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +1 +\end_layout + +\end_inset +</cell> +</row> +<row> +<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +1 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +1 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +1 +\end_layout + +\end_inset +</cell> +</row> +<row> +<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +2 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +1 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +1 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +2 +\end_layout + +\end_inset +</cell> +</row> +<row> +<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +3 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +1 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +3 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +1 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +5 +\end_layout + +\end_inset +</cell> +</row> +<row> +<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +4 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +1 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +7 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +6 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +1 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +15 +\end_layout + +\end_inset +</cell> +</row> +<row> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +5 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +0 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +1 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +15 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +25 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +10 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +1 +\end_layout + +\end_inset +</cell> +<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none"> +\begin_inset Text + +\begin_layout Plain Layout +52 +\end_layout + +\end_inset +</cell> +</row> +</lyxtabular> + +\end_inset + + +\end_layout + +\begin_layout Plain Layout +\begin_inset Caption Standard + +\begin_layout Plain Layout +Stirlingova števila druge vrste +\end_layout + +\end_inset + + +\end_layout + +\begin_layout Plain Layout + +\end_layout + +\end_inset + + +\end_layout + +\begin_layout Standard +To nas spomni na ekvivalenčne razrede. +\end_layout + +\begin_layout Definition* +Ekvivalenčna relacija je refleksivna ( +\begin_inset Formula $x\sim x$ +\end_inset + +), + simetrična ( +\begin_inset Formula $x\sim y\Rightarrow y\sim x$ +\end_inset + +) in tranzitivna ( +\begin_inset Formula $x\sim y\wedge y\sim z\Rightarrow x\sim z$ +\end_inset + +). +\end_layout + +\begin_layout Remark* +Množica razpade na ekvivalenčne razrede, + ki tvorijo razdelitev. + +\begin_inset Formula $S\left(n,k\right)$ +\end_inset + + je število ekvivalenčnih relacij na +\begin_inset Formula $\left[n\right]$ +\end_inset + + s +\begin_inset Formula $k$ +\end_inset + + ekvivalenčnimi razredi. + +\begin_inset Formula $B\left(n\right)$ +\end_inset + + je število ekvivalenčnih relacij na +\begin_inset Formula $\left[n\right]$ +\end_inset + +. +\end_layout + +\begin_layout Remark* +Za surjekcijo +\begin_inset Formula $f:\left[n\right]\to\left[k\right]$ +\end_inset + + velja +\begin_inset Formula $\forall i\in\left[k\right]:f^{-1}\left(i\right)\not=\emptyset$ +\end_inset + + (praslika je neprazna množica). + Ker je +\begin_inset Formula $f$ +\end_inset + + funkcija, + velja +\begin_inset Formula $\forall i,j\in\left[k\right]:i\not=j\Rightarrow f^{-1}\left(i\right)\cap f^{-1}\left(i\right)=\emptyset$ +\end_inset + + in +\begin_inset Formula $\bigcup_{i=1}^{k}f^{-1}\left(i\right)=\left[n\right]$ +\end_inset + +. + Surjekcija pa vseeno ni isto kot razdelitev — + pomemben je vrstni red blokov. +\end_layout + +\begin_layout Question* +Koliko surjekcij je iz +\begin_inset Formula $\left[n\right]$ +\end_inset + + v +\begin_inset Formula $\left[k\right]$ +\end_inset + +? + Odgovor: + +\begin_inset Formula $S\left(n,k\right)\cdot k!$ +\end_inset + + — + Surjekcija je razdelitev z vrstnim redom blokov. + Koliko je +\begin_inset Formula $\left[4\right]\to\left[2\right]$ +\end_inset + + surjekcij? + Odgovor: + +\begin_inset Formula $S\left(4,2\right)\cdot2!=7\cdot2=14$ +\end_inset + + +\end_layout + +\begin_layout Definition* +Premestitve so permutacije brez negibne točke. +\end_layout + +\begin_layout Corollary* +Od prej se spomnimo, + da je število surjekcij iz +\begin_inset Formula $\left[n\right]$ +\end_inset + + v +\begin_inset Formula $\left[k\right]$ +\end_inset + + enako +\begin_inset Formula $\sum_{j=0}^{k}\left(-1\right)^{k-j}\binom{k}{j}j^{n}$ +\end_inset + +. + Posledično je +\begin_inset Formula $S\left(n,k\right)=\sum_{j=0}^{k}\frac{\left(-1\right)^{k-j}j^{n}}{j!\left(k-j\right)!}$ +\end_inset + +. +\end_layout + +\begin_layout Example* +\begin_inset Formula +\[ +S\left(n,2\right)=\frac{2^{n}}{2}-\frac{1}{1}+\frac{\delta_{0,n}}{2!\cdot0!}=2^{n-1}-1+\frac{\delta_{n,0}}{2} +\] + +\end_inset + +Razdelimo +\begin_inset Formula $n$ +\end_inset + + elementov v 2 bloka. + Fiksirajmo +\begin_inset Formula $1$ +\end_inset + + v prvi blok, + za vsak preostali ( +\begin_inset Formula $n-1$ +\end_inset + + jih ostane) element pa imamo dvojiški enum, + ki pove, + v katerem bloku je. + +\begin_inset Formula $-1$ +\end_inset + + zato, + ker mora biti drugi blok neprazen in izločimo opcijo, + kjer so vsi dvojiški enumi enaki 0, + +\begin_inset Formula $\delta_{n,0}$ +\end_inset + + zato, + da popravimo primer, + ko je +\begin_inset Formula $n=0$ +\end_inset + +. +\end_layout + +\begin_layout Theorem* +\begin_inset Formula $\sum_{k}S\left(n,k\right)x^{k}=?$ +\end_inset + + TODO XXX FIXME NE RAZUMEM +\end_layout + +\begin_layout Example* +\begin_inset Formula $n=3$ +\end_inset + +: + +\begin_inset Formula $\sum_{k}S\left(3,k\right)x^{k}=x+3x^{2}+x^{3}=?$ +\end_inset + + +\end_layout + +\begin_layout Theorem* +\begin_inset Formula $\sum_{k}S\left(n,k\right)x^{\underline{k}}=x^{n}$ +\end_inset + + +\end_layout + +\begin_layout Example* +\begin_inset Formula $n=3$ +\end_inset + +: + +\begin_inset Formula $\sum_{k}S\left(3,k\right)x^{\underline{k}}=x+3x\left(x-1\right)+x\left(x-1\right)\left(x-2\right)=x\left(1\cancel{+3x}-3+x^{2}\cancel{-3x}+2\right)=x\left(\cancel{1-3}+x^{2}\cancel{+2}\right)=x^{3}$ +\end_inset + + +\end_layout + +\begin_layout Proof +Več načinov. +\end_layout + +\begin_deeper +\begin_layout Itemize +Indukcija. + (na vajah) +\end_layout + +\begin_layout Itemize +Kombinatorično: + +\begin_inset Formula $x^{n}$ +\end_inset + +: + štetje +\end_layout + +\begin_deeper +\begin_layout Itemize +nizov dolžine +\begin_inset Formula $n$ +\end_inset + + z elementi iz +\begin_inset Formula $\left[x\right]$ +\end_inset + + +\end_layout + +\begin_layout Itemize +preslikav iz +\begin_inset Formula $\left[n\right]$ +\end_inset + + v +\begin_inset Formula $\left[x\right]=\left|\left[x\right]^{\left[n\right]}\right|$ +\end_inset + +. + Vsaka preslikava je surjekcija na svojo sliko. + Oglejmo si vse slike +\begin_inset Formula $T\subseteq\left[x\right]$ +\end_inset + +: +\begin_inset Formula +\[ +x^{n}=\left|\left[x\right]^{\left[n\right]}\right|=\sum_{T\subseteq\left[x\right]}\left|T\right|!\cdot S\left(n,\left|T\right|\right)\overset{\text{po močeh \left|T\right|}}{=}\sum_{k}k!\cdot S\left(n,k\right){x \choose k}\overset{{x \choose k}=\frac{x^{\underline{k}}}{k!}}{=}\sum_{k}S\left(n,k\right)x^{\underline{k}} +\] + +\end_inset + + +\end_layout + +\begin_deeper +\begin_layout Standard +Dokaz je veljaven za +\begin_inset Formula $x\in\mathbb{N}_{0}$ +\end_inset + +. + Da dokažemo, + da sta dva polinoma stopnje +\begin_inset Formula $\leq n$ +\end_inset + + enaka, + je dovolj preveriti ujemanje v +\begin_inset Formula $n+1$ +\end_inset + + različnih točkah, + kajti razlika je polinom stopnje +\begin_inset Formula $\leq n$ +\end_inset + +, + če ni ničeln ima +\begin_inset Formula $\leq n$ +\end_inset + + ničel, + kar je v neskladju s tem, + da se polinoma ujemata v +\begin_inset Formula $n+1$ +\end_inset + + točkah (v ničlah se ne). + Nmamo polinoma stopnje +\begin_inset Formula $n$ +\end_inset + +, + ki se ujemata v +\begin_inset Formula $\infty$ +\end_inset + + točkah, + torej sta enaka. + Torej je dokaz veljaven tudi za realna števila. +\end_layout + +\end_deeper +\end_deeper +\end_deeper +\begin_layout Subsection +Lahova števila +\end_layout + +\begin_layout Standard +Imenujejo se po slovenskem aktuarju Ivu Lahu. +\end_layout + +\begin_layout Definition* +\begin_inset Formula $L\left(n,k\right)$ +\end_inset + + je število razdelitev +\begin_inset Formula $\left[n\right]$ +\end_inset + + na +\begin_inset Formula $k$ +\end_inset + + linearno urejenih blokov. + +\begin_inset Formula $\left\{ 142,3674\right\} =\left\{ 3674,152\right\} $ +\end_inset + +, + toda +\begin_inset Formula $\left\{ 152,3674\right\} \not=\left\{ 125,3764\right\} $ +\end_inset + +. + Vrstni red znotraj bloka je pomemben, + ni pa pomemben vrstni red blokov. +\end_layout + +\begin_layout Example* +\begin_inset Formula $L\left(4,2\right)$ +\end_inset + +: + +\begin_inset Formula $\left\{ \left(\_\right),\left(\_,\_,\_\right)\right\} $ +\end_inset + + +\begin_inset Formula $\times4\cdot3!$ +\end_inset + +, + +\begin_inset Formula $\left\{ \left(\_,\_\right),\left(\_,\_\right)\right\} $ +\end_inset + + +\begin_inset Formula $\times3\cdot2!\cdot2!$ +\end_inset + + (enka v prvem bloku, + vrstni red v 1. + bloku, + vrstni red v 2. + bloku) +\begin_inset Formula $\Longrightarrow24+12=36=L\left(4,2\right)$ +\end_inset + +. +\end_layout + +\begin_layout Claim* +Rekurzivna zveza za Lahova števila: + +\begin_inset Formula $L\left(n,k\right)=L\left(n-1,k-1\right)+L\left(n-1,k\right)\cdot\left(n-1+k\right)$ +\end_inset + + +\end_layout + +\begin_layout Proof +Ločimo razdelitve +\begin_inset Formula $\left[n\right]$ +\end_inset + + na +\begin_inset Formula $k$ +\end_inset + + linearno urejenih blokov v dve disjunktni podmnožici: +\end_layout + +\begin_deeper +\begin_layout Itemize +\begin_inset Formula $\left(n\right)$ +\end_inset + + je blok: + takih je +\begin_inset Formula $L\left(n-1,k-1\right)$ +\end_inset + + +\end_layout + +\begin_layout Itemize +\begin_inset Formula $\left(n\right)$ +\end_inset + + ni blok: + takih je +\begin_inset Formula $L\left(n-1,k\right)\cdot\left(n-1+k\right)$ +\end_inset + + — + +\begin_inset Formula $n$ +\end_inset + + lahko vstavimo nazaj bodisi za nek element ( +\begin_inset Formula $n-1$ +\end_inset + + opcij) ali na začetek enega izmed blokov ( +\begin_inset Formula $k$ +\end_inset + + opcij) +\end_layout + +\end_deeper +\begin_layout Claim* +\begin_inset Formula $L\left(n,k\right)=\frac{n!}{k!}{k-1 \choose n-1}$ +\end_inset + + za +\begin_inset Formula $n,k\geq1$ +\end_inset + + +\end_layout + +\begin_layout Example* +\begin_inset Formula $L\left(4,2\right)=\frac{4!}{2!}{3 \choose 1}=36$ +\end_inset + +, + +\begin_inset Formula $L\left(n,n\right)=1$ +\end_inset + +, + +\begin_inset Formula $L\left(n,1\right)=n!$ +\end_inset + +, + +\begin_inset Formula $L\left(n,n-1\right)=n\left(n-1\right)$ +\end_inset + + +\end_layout + +\begin_layout Proof +Preštejmo urejene razdelitve na linearno urejene bloke na dva načina: +\end_layout + +\begin_deeper +\begin_layout Standard +uredimo bloke in množimo z razdelitvami +\begin_inset Formula $=k!\cdot L\left(n,k\right)=n!{n-1 \choose k-1}=$ +\end_inset + + permutacije množimo s kompozicijami (pregrade) +\end_layout + +\end_deeper +\begin_layout Theorem* +\begin_inset Formula +\[ +\sum_{k}L\left(n,k\right)x^{\underline{k}}=x^{\overline{n}} +\] + +\end_inset + + +\end_layout + +\begin_layout Proof +Induktivni. + Baza +\begin_inset Formula $n=0$ +\end_inset + +. + Korak +\begin_inset Formula $n-1\to n$ +\end_inset + +: +\begin_inset Formula +\[ +x^{\overline{n}}=x^{\overline{n-1}}\left(x+n-1\right)=\left(\sum_{k}L\left(n-1,k\right)x^{\underline{k}}\right)\cdot\left(x+n-1=\left(x-k\right)+\left(n+k-1\right)\right)= +\] + +\end_inset + + +\begin_inset Formula +\[ +=\sum_{k}L\left(n-1,k\right)x^{\underline{k+1}}\left(+\sum_{k}L\left(n-1,k\right)x^{\underline{k}}\right)\cdot\left(n+k-1\right)=\sum_{k}L\left(n-1,k-1\right)x^{\underline{k}}+\left(\sum_{k}L\left(n-1,k\right)x^{\underline{k}}\right)\cdot\left(n+k-1\right)=\sum_{k}L\left(n,k\right)x^{\underline{k}} +\] + +\end_inset + + +\end_layout + +\begin_layout Remark* +Nekaj opomb. +\begin_inset Formula +\[ +S\left(n,k\right)\leq c\left(n,k\right)\leq L\left(n,k\right) +\] + +\end_inset + + +\begin_inset Formula +\[ +\sum_{k}c\left(n,k\right)x^{\underline{k}}=x^{n} +\] + +\end_inset + + +\begin_inset Formula +\[ +\sum_{k}L\left(n,k\right)x^{\underline{k}}=x^{\overline{n}} +\] + +\end_inset + + +\begin_inset Formula +\[ +\sum_{k}c\left(n,k\right)\left(-1\right)^{k}x^{k}=\left(-1\right)^{n}x^{\underline{n}} +\] + +\end_inset + + +\begin_inset Formula +\[ +\sum_{k}\left(-1\right)^{n-k}c\left(n,k\right)x^{k}=x^{\underline{n}} +\] + +\end_inset + + +\begin_inset Formula +\[ +\sum_{k}\left(-1\right)^{n-k}S\left(n,k\right)x^{\overline{k}}=x^{n} +\] + +\end_inset + + +\begin_inset Formula +\[ +\sum_{k}\left(-1\right)^{n-k}L\left(n,k\right)x^{\overline{k}}=x^{\underline{n}} +\] + +\end_inset + + +\end_layout + +\begin_layout Paragraph* +Operacije v algebri +\end_layout + +\begin_layout Standard +seštevanje, + množenje, + množenje s skalarjem. +\end_layout + +\begin_layout Standard +seštevanje+množenje nam data kolobar, + seštevanje in množenje s skalarjem vektorski prostor, + vse troje pa (komutativno) algebro. +\end_layout + +\begin_layout Example* +\begin_inset Formula $m\times m$ +\end_inset + + matrike so nekomutativne algebre. +\end_layout + +\begin_layout Standard +\begin_inset Separator plain +\end_inset + + +\end_layout + +\begin_layout Example* +\begin_inset Formula $\mathbb{R}\left[x\right]$ +\end_inset + + je neskončnorazsežen vektorski prostor. + Ena baza je +\begin_inset Formula $\left\{ 1,x,x^{2},\dots\right\} $ +\end_inset + +, + spet druga je +\begin_inset Formula $\left\{ 1,x,x^{\underline{2}},x^{\underline{3}},\dots\right\} $ +\end_inset + +, + še ena je +\begin_inset Formula $\left\{ 1,x,x^{\overline{2}},x^{\overline{3}},\dots\right\} $ +\end_inset + +. +\end_layout + +\begin_layout Remark* +Naših šest polinomskih zvez nam daje prehodne matrike med bazami. + +\begin_inset Formula $\left(-1\right)^{n-k}c\left(n,k\right)\eqqcolon s\left(n,k\right)$ +\end_inset + + (predznačeno stirlingovo število prve vrste). +\end_layout + +\begin_layout Subsection +Razčlenitve in eulerjev petkotniški izrek +\end_layout + +\begin_layout Definition* +Razčlenitev (angl. + integer partition) +\begin_inset Formula $n\in\mathbb{N}_{0}$ +\end_inset + + je zaporedje +\begin_inset Formula $\lambda_{1},\dots,\lambda_{l}$ +\end_inset + +; + +\begin_inset Formula $\forall i\in\left[l\right]:\lambda_{l}>0$ +\end_inset + +, + +\begin_inset Formula $\lambda_{1}\geq\lambda_{2}\geq\cdots\geq\lambda_{l}$ +\end_inset + +, + +\begin_inset Formula $\lambda_{1}+\cdots+\lambda_{l}=n$ +\end_inset + +. + Dodaten pogoj za razliko od kompozicij je linearna urejenost zaporedja (vrstni red ni pomemben). + +\begin_inset Formula $\lambda_{i}$ +\end_inset + + so členi razčlenitve, + +\begin_inset Formula $l$ +\end_inset + + je njena dolžina in +\begin_inset Formula $n$ +\end_inset + + njena velikost. + S +\begin_inset Formula $p_{k}\left(n\right)$ +\end_inset + + označimo število razčlenitev +\begin_inset Formula $n$ +\end_inset + + dolžine +\begin_inset Formula $k$ +\end_inset + +, + s +\begin_inset Formula $\overline{p_{k}}\left(n\right)$ +\end_inset + + označimo število razčlenitev dolžine +\begin_inset Formula $\leq k$ +\end_inset + +, + s +\begin_inset Formula $p\left(n\right)$ +\end_inset + + pa število razčlenitev +\begin_inset Formula $n$ +\end_inset + + (vseh dolžin). +\end_layout + +\end_body +\end_document |