\documentclass[10pt,a4paper]{article} % Packages \usepackage{fancyhdr} % For header and footer \usepackage{multicol} % Allows multicols in tables \usepackage{tabularx} % Intelligent column widths \usepackage{tabulary} % Used in header and footer \usepackage{hhline} % Border under tables \usepackage{graphicx} % For images \usepackage{xcolor} % For hex colours %\usepackage[utf8x]{inputenc} % For unicode character support \usepackage[T1]{fontenc} % Without this we get weird character replacements \usepackage{colortbl} % For coloured tables \usepackage{setspace} % For line height \usepackage{lastpage} % Needed for total page number \usepackage{seqsplit} % Splits long words. %\usepackage{opensans} % Can't make this work so far. Shame. Would be lovely. \usepackage[normalem]{ulem} % For underlining links % Most of the following are not required for the majority % of cheat sheets but are needed for some symbol support. \usepackage{amsmath} % Symbols \usepackage{MnSymbol} % Symbols \usepackage{wasysym} % Symbols %\usepackage[english,german,french,spanish,italian]{babel} % Languages % Document Info \author{LuciaZhang} \pdfinfo{ /Title (appendix-b-measure-and-probability-theory.pdf) /Creator (Cheatography) /Author (LuciaZhang) /Subject (Appendix B+ - Measure \& Probability Theory Cheat Sheet) } % Lengths and widths \addtolength{\textwidth}{6cm} \addtolength{\textheight}{-1cm} \addtolength{\hoffset}{-3cm} \addtolength{\voffset}{-2cm} \setlength{\tabcolsep}{0.2cm} % Space between columns \setlength{\headsep}{-12pt} % Reduce space between header and content \setlength{\headheight}{85pt} % If less, LaTeX automatically increases it \renewcommand{\footrulewidth}{0pt} % Remove footer line \renewcommand{\headrulewidth}{0pt} % Remove header line \renewcommand{\seqinsert}{\ifmmode\allowbreak\else\-\fi} % Hyphens in seqsplit % This two commands together give roughly % the right line height in the tables \renewcommand{\arraystretch}{1.3} \onehalfspacing % Commands \newcommand{\SetRowColor}[1]{\noalign{\gdef\RowColorName{#1}}\rowcolor{\RowColorName}} % Shortcut for row colour \newcommand{\mymulticolumn}[3]{\multicolumn{#1}{>{\columncolor{\RowColorName}}#2}{#3}} % For coloured multi-cols \newcolumntype{x}[1]{>{\raggedright}p{#1}} % New column types for ragged-right paragraph columns \newcommand{\tn}{\tabularnewline} % Required as custom column type in use % Font and Colours \definecolor{HeadBackground}{HTML}{333333} \definecolor{FootBackground}{HTML}{666666} \definecolor{TextColor}{HTML}{333333} \definecolor{DarkBackground}{HTML}{106EA3} \definecolor{LightBackground}{HTML}{F0F5F9} \renewcommand{\familydefault}{\sfdefault} \color{TextColor} % Header and Footer \pagestyle{fancy} \fancyhead{} % Set header to blank \fancyfoot{} % Set footer to blank \fancyhead[L]{ \noindent \begin{multicols}{3} \begin{tabulary}{5.8cm}{C} \SetRowColor{DarkBackground} \vspace{-7pt} {\parbox{\dimexpr\textwidth-2\fboxsep\relax}{\noindent \hspace*{-6pt}\includegraphics[width=5.8cm]{/web/www.cheatography.com/public/images/cheatography_logo.pdf}} } \end{tabulary} \columnbreak \begin{tabulary}{11cm}{L} \vspace{-2pt}\large{\bf{\textcolor{DarkBackground}{\textrm{Appendix B+ - Measure \& Probability Theory Cheat Sheet}}}} \\ \normalsize{by \textcolor{DarkBackground}{LuciaZhang} via \textcolor{DarkBackground}{\uline{cheatography.com/136048/cs/48168/}}} \end{tabulary} \end{multicols}} \fancyfoot[L]{ \footnotesize \noindent \begin{multicols}{3} \begin{tabulary}{5.8cm}{LL} \SetRowColor{FootBackground} \mymulticolumn{2}{p{5.377cm}}{\bf\textcolor{white}{Cheatographer}} \\ \vspace{-2pt}LuciaZhang \\ \uline{cheatography.com/luciazhang} \\ \end{tabulary} \vfill \columnbreak \begin{tabulary}{5.8cm}{L} \SetRowColor{FootBackground} \mymulticolumn{1}{p{5.377cm}}{\bf\textcolor{white}{Cheat Sheet}} \\ \vspace{-2pt}Not Yet Published.\\ Updated 6th June, 2026.\\ Page {\thepage} of \pageref{LastPage}. \end{tabulary} \vfill \columnbreak \begin{tabulary}{5.8cm}{L} \SetRowColor{FootBackground} \mymulticolumn{1}{p{5.377cm}}{\bf\textcolor{white}{Sponsor}} \\ \SetRowColor{white} \vspace{-5pt} %\includegraphics[width=48px,height=48px]{dave.jpeg} Measure your website readability!\\ www.readability-score.com \end{tabulary} \end{multicols}} \begin{document} \raggedright \raggedcolumns % Set font size to small. Switch to any value % from this page to resize cheat sheet text: % www.emerson.emory.edu/services/latex/latex_169.html \footnotesize % Small font. \begin{multicols*}{3} \begin{tabularx}{5.377cm}{x{1.9908 cm} x{2.9862 cm} } \SetRowColor{DarkBackground} \mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{σ-algebras \& Borel sets}} \tn % Row 0 \SetRowColor{LightBackground} A ⊆ 2\textasciicircum{}Ω\textasciicircum{} is a σ-algebra & if Ω ∈ A, A ∈ A ⇒ A\textasciicircum{}c\textasciicircum{} ∈ A, and A\textasciitilde{}i\textasciitilde{} ∈ A ⇒ ⋃\textasciitilde{}i∈N\textasciitilde{} A\textasciitilde{}i\textasciitilde{} ∈ A \tn % Row Count 4 (+ 4) % Row 1 \SetRowColor{white} σ(E) & intersection of all σ-algebras containing E \tn % Row Count 6 (+ 2) % Row 2 \SetRowColor{LightBackground} ℬ(V) & σ(open subsets of V) \tn % Row Count 7 (+ 1) \hhline{>{\arrayrulecolor{DarkBackground}}--} \end{tabularx} \par\addvspace{1.3em} \begin{tabularx}{5.377cm}{x{1.59264 cm} x{3.38436 cm} } \SetRowColor{DarkBackground} \mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Measures}} \tn % Row 0 \SetRowColor{LightBackground} Measure\{\{width=35\}\} & μ(∅)=0 and μ(⋃ A\textasciitilde{}i\textasciitilde{})=Σ μ(A\textasciitilde{}i\textasciitilde{}) for disjoint A\textasciitilde{}i\textasciitilde{} \tn % Row Count 3 (+ 3) % Row 1 \SetRowColor{white} Probability & P(Ω)=1 \tn % Row Count 4 (+ 1) % Row 2 \SetRowColor{LightBackground} Product & (⊗\textasciitilde{}j\textasciitilde{}μ\textasciitilde{}j\textasciitilde{})(A\textasciitilde{}1\textasciitilde{} × ... × A\textasciitilde{}n\textasciitilde{})=∏\textasciitilde{}j\textasciitilde{} μ\textasciitilde{}j\textasciitilde{}(A\textasciitilde{}j\textasciitilde{}) \tn % Row Count 6 (+ 2) % Row 3 \SetRowColor{white} Lebesgue & λ\textasciicircum{}d\textasciicircum{}(∏\textasciitilde{}j\textasciitilde{} (a\textasciitilde{}j\textasciitilde{},b\textasciitilde{}j\textasciitilde{})) = ∏\textasciitilde{}j\textasciitilde{} (b\textasciitilde{}j\textasciitilde{}-a\textasciitilde{}j\textasciitilde{}) \tn % Row Count 8 (+ 2) \hhline{>{\arrayrulecolor{DarkBackground}}--} \end{tabularx} \par\addvspace{1.3em} \begin{tabularx}{5.377cm}{x{1.74195 cm} x{3.23505 cm} } \SetRowColor{DarkBackground} \mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Measurability}} \tn % Row 0 \SetRowColor{LightBackground} Measurable\{\{width=33\}\} & f\textasciicircum{}-1\textasciicircum{}(A\textasciitilde{}2\textasciitilde{}) ∈ 𝒜\textasciitilde{}1\textasciitilde{} for all A\textasciitilde{}2\textasciitilde{} ∈ 𝒜\textasciitilde{}2\textasciitilde{} \tn % Row Count 2 (+ 2) % Row 1 \SetRowColor{white} Check on generators & 𝒜\textasciitilde{}2\textasciitilde{}=σ(ℰ), enough to check\{\{nl\}\} f\textasciicircum{}-1\textasciicircum{}(E) ∈ A\textasciitilde{}1\textasciitilde{} for E ∈ ℰ \tn % Row Count 5 (+ 3) % Row 2 \SetRowColor{LightBackground} Strongly measurable & f\textasciitilde{}n\textasciitilde{} simple, f\textasciitilde{}n\textasciitilde{} → f pointwise or μ-a.e. \tn % Row Count 7 (+ 2) % Row 3 \SetRowColor{white} Pettis & f strongly measurable ⇔ f separably valued and ⟨f,v′⟩ measurable for every v′ ∈ V \tn % Row Count 11 (+ 4) \hhline{>{\arrayrulecolor{DarkBackground}}--} \end{tabularx} \par\addvspace{1.3em} \begin{tabularx}{5.377cm}{x{1.69218 cm} x{3.28482 cm} } \SetRowColor{DarkBackground} \mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Bochner integration, change of variables}} \tn % Row 0 \SetRowColor{LightBackground} μ-simple\{\{width=33\}\} & f = Σ\textasciitilde{}j=1\textasciitilde{}\textasciicircum{}n\textasciicircum{} 1\textasciitilde{}A\_j\textasciitilde{} v\textasciitilde{}j\textasciitilde{}, μ(A\textasciitilde{}j\textasciitilde{}) \textless{} ∞ \tn % Row Count 2 (+ 2) % Row 1 \SetRowColor{white} & ∫ f dμ = Σ μ(A\textasciitilde{}j\textasciitilde{}) v\textasciitilde{}j\textasciitilde{} for simple f \tn % Row Count 4 (+ 2) % Row 2 \SetRowColor{LightBackground} Bochner definition & f\_n→f μ-a.e. and ∫ ||f-f\_n|| dμ→0 \tn % Row Count 6 (+ 2) % Row 3 \SetRowColor{white} Bochner criterion & f strongly μ-measurable, ∫ ||f|| dμ \textless{} ∞ \tn % Row Count 8 (+ 2) % Row 4 \SetRowColor{LightBackground} Norm bound & ||∫ f dμ|| ≤ ∫ ||f|| dμ \tn % Row Count 10 (+ 2) % Row 5 \SetRowColor{white} Duality & ⟨∫ f dμ, v′⟩ = ∫ ⟨f,v′⟩ dμ \tn % Row Count 12 (+ 2) % Row 6 \SetRowColor{LightBackground} L\textasciicircum{}p\textasciicircum{} & μ-a.e. equivalence classes of strongly μ-measurable functions with finite L\textasciicircum{}p\textasciicircum{} norm \tn % Row Count 16 (+ 4) % Row 7 \SetRowColor{white} dν/dμ & density of ν w.r.t μ, ν ≪ μ \tn % Row Count 18 (+ 2) % Row 8 \SetRowColor{LightBackground} Pushforward & T\textasciitilde{}\#\textasciitilde{} μ(A) = μ(T\textasciicircum{}-1\textasciicircum{}(A))\{\{nl\}\} ∫ f d(T\textasciitilde{}\#\textasciitilde{}μ) = ∫ f∘T dμ \tn % Row Count 21 (+ 3) \hhline{>{\arrayrulecolor{DarkBackground}}--} \end{tabularx} \par\addvspace{1.3em} \begin{tabularx}{5.377cm}{x{2.33919 cm} x{2.63781 cm} } \SetRowColor{DarkBackground} \mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Banach-valued RVs}} \tn % Row 0 \SetRowColor{LightBackground} Random variable\{\{width=30\}\} & X:(Ω,A)→(V,B(V)) measurable \tn % Row Count 2 (+ 2) % Row 1 \SetRowColor{white} \mymulticolumn{2}{x{5.377cm}}{P\textasciitilde{}X\textasciitilde{} = X\textasciitilde{}\#\textasciitilde{}P, so P{[}X ∈ B{]}=P\textasciitilde{}X\textasciitilde{}(B)} \tn % Row Count 3 (+ 1) % Row 2 \SetRowColor{LightBackground} \mymulticolumn{2}{x{5.377cm}}{σ(X) = \{X\textasciicircum{}-1\textasciicircum{}(B): B ∈ ℬ(V)\}} \tn % Row Count 4 (+ 1) % Row 3 \SetRowColor{white} \mymulticolumn{2}{x{5.377cm}}{E{[}X{]} = ∫\textasciitilde{}Ω\textasciitilde{} X(ω)dP(ω), if ∫ ||X|| dP \textless{} ∞} \tn % Row Count 5 (+ 1) % Row 4 \SetRowColor{LightBackground} \mymulticolumn{2}{x{5.377cm}}{E{[}φ(X){]} = ∫\textasciitilde{}Ω\textasciitilde{} φ(X(ω))dP(ω) = ∫\textasciitilde{}V\textasciitilde{} φ(v)dP\textasciitilde{}X\textasciitilde{}(v)} \tn % Row Count 7 (+ 2) \hhline{>{\arrayrulecolor{DarkBackground}}--} \end{tabularx} \par\addvspace{1.3em} \begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} } \SetRowColor{DarkBackground} \mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Conditional probability \& independence}} \tn % Row 0 \SetRowColor{LightBackground} \mymulticolumn{2}{x{5.377cm}}{P{[}A|B{]} = P{[}A∩B{]}/P{[}B{]}, P{[}B{]}\textgreater{}0} \tn % Row Count 1 (+ 1) % Row 1 \SetRowColor{white} \mymulticolumn{2}{x{5.377cm}}{A,B independent ⇔ P{[}A∩B{]}=P{[}A{]}P{[}B{]}} \tn % Row Count 2 (+ 1) % Row 2 \SetRowColor{LightBackground} \mymulticolumn{2}{x{5.377cm}}{X\textasciitilde{}i\textasciitilde{} independent ⇔ σ(X\textasciitilde{}i\textasciitilde{}) independent} \tn % Row Count 3 (+ 1) % Row 3 \SetRowColor{white} \mymulticolumn{2}{x{5.377cm}}{If X\textasciitilde{}1\textasciitilde{},...,X\textasciitilde{}n\textasciitilde{} independent and integrable: E{[}∏X\textasciitilde{}i\textasciitilde{}{]}=∏E{[}X\textasciitilde{}i\textasciitilde{}{]}} \tn % Row Count 5 (+ 2) \hhline{>{\arrayrulecolor{DarkBackground}}--} \end{tabularx} \par\addvspace{1.3em} \begin{tabularx}{5.377cm}{x{2.4885 cm} x{2.4885 cm} } \SetRowColor{DarkBackground} \mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Conditional expectation}} \tn % Row 0 \SetRowColor{LightBackground} For simple Y = Σ 1\textasciitilde{}A\_j\textasciitilde{} y\textasciitilde{}j\textasciitilde{} \{\{width=35\}\} & E`{[}X|Y{]}`(ω) = 1/P{[}A\textasciitilde{}j\textasciitilde{}{]}∫\textasciitilde{}A\_j\textasciitilde{}X dP for ω ∈ A\textasciitilde{}j\textasciitilde{} \tn % Row Count 3 (+ 3) % Row 1 \SetRowColor{white} Z=E{[}X|ℱ{]} & iff Z is ℱ-measurable and \{\{nl\}\}∫\textasciitilde{}B\textasciitilde{}Z dP=∫\textasciitilde{}B\textasciitilde{} X dP for all B ∈ F \tn % Row Count 7 (+ 4) % Row 2 \SetRowColor{LightBackground} \mymulticolumn{2}{x{5.377cm}}{E{[}X|Y{]} := E{[}X|σ(Y){]}, P{[}A|Y{]} := E{[}1\textasciitilde{}A\textasciitilde{}|σ(Y){]}} \tn % Row Count 8 (+ 1) \hhline{>{\arrayrulecolor{DarkBackground}}--} \end{tabularx} \par\addvspace{1.3em} \begin{tabularx}{5.377cm}{x{1.4931 cm} x{3.4839 cm} } \SetRowColor{DarkBackground} \mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Regular conditional distributions \& Doob-Dynkin}} \tn % Row 0 \SetRowColor{LightBackground} \{\{width=35\}\}Goal: & define P{[}X ∈ B | Y=y{]} even when P{[}Y=y{]}=0 \tn % Row Count 2 (+ 2) % Row 1 \SetRowColor{white} \mymulticolumn{2}{x{5.377cm}}{κ\textasciitilde{}X|F\textasciitilde{}: Ω × ℬ(V) → {[}0,1{]}} \tn % Row Count 3 (+ 1) % Row 2 \SetRowColor{LightBackground} \mymulticolumn{2}{x{5.377cm}}{For A∈ℱ, B∈ℬ(V): P{[}A∩\{X∈B\}{]} = ∫\textasciitilde{}A\textasciitilde{} κ\textasciitilde{}X|F\textasciitilde{}(ω,B)dP(ω)} \tn % Row Count 5 (+ 2) % Row 3 \SetRowColor{white} Doob-Dynkin & κ σ(Y)-measurable ⇔ κ = τ∘Y for measurable τ \tn % Row Count 7 (+ 2) % Row 4 \SetRowColor{LightBackground} \mymulticolumn{2}{x{5.377cm}}{τ\textasciitilde{}X|Y\textasciitilde{}(y,B) := P{[}X∈B | Y=y{]}} \tn % Row Count 8 (+ 1) \hhline{>{\arrayrulecolor{DarkBackground}}--} \end{tabularx} \par\addvspace{1.3em} \begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} } \SetRowColor{DarkBackground} \mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Conditional densities}} \tn % Row 0 \SetRowColor{LightBackground} \mymulticolumn{2}{x{5.377cm}}{f\textasciitilde{}Y\textasciitilde{}(y) = ∫\textasciitilde{}R\textasciicircum{}m\textasciitilde{} f\textasciitilde{}X,Y\textasciitilde{}(x,y) dx} \tn % Row Count 1 (+ 1) % Row 1 \SetRowColor{white} \mymulticolumn{2}{x{5.377cm}}{f\textasciitilde{}X|Y\textasciitilde{}(x|y) = f\textasciitilde{}X,Y\textasciitilde{}(x,y)/f\textasciitilde{}Y\textasciitilde{}(y), for f\textasciitilde{}Y\textasciitilde{}(y)\textgreater{}0} \tn % Row Count 2 (+ 1) % Row 2 \SetRowColor{LightBackground} \mymulticolumn{2}{x{5.377cm}}{P{[}X ∈ B | Y=y{]} = ∫\textasciitilde{}B\textasciitilde{} f\textasciitilde{}X|Y\textasciitilde{}(x|y) dx} \tn % Row Count 3 (+ 1) \hhline{>{\arrayrulecolor{DarkBackground}}--} \end{tabularx} \par\addvspace{1.3em} \begin{tabularx}{5.377cm}{x{2.04057 cm} x{2.93643 cm} } \SetRowColor{DarkBackground} \mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Gaussians}} \tn % Row 0 \SetRowColor{LightBackground} X∼N(μ,σ$^{\textrm{2}}$): \{\{width=20\}\} & f\textasciitilde{}X\textasciitilde{}(x) = 1/√(2πσ$^{\textrm{2}}$) exp(−(x−μ)$^{\textrm{2}}$/ (2σ$^{\textrm{2}}$)) \tn % Row Count 3 (+ 3) % Row 1 \SetRowColor{white} X∼N(μ,Σ): & f\textasciitilde{}X\textasciitilde{}(x) ∝ det(Σ)\textasciicircum{}-1/2\textasciicircum{} exp(−1/2 (x−μ)\textasciicircum{}T\textasciicircum{}Σ\textasciicircum{}-1\textasciicircum{}(x−μ)) \tn % Row Count 6 (+ 3) % Row 2 \SetRowColor{LightBackground} Gaussian facts & marginals Gaussian; conditionals Gaussian; jointly Gaussian + uncorrelated ⇔ independent \tn % Row Count 10 (+ 4) \hhline{>{\arrayrulecolor{DarkBackground}}--} \end{tabularx} \par\addvspace{1.3em} \begin{tabularx}{5.377cm}{x{1.4931 cm} x{3.4839 cm} } \SetRowColor{DarkBackground} \mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Distances \& Divergences}} \tn % Row 0 \SetRowColor{LightBackground} \mymulticolumn{2}{x{5.377cm}}{D\textasciitilde{}TV\textasciitilde{}(P,Q) = sup\textasciitilde{}A∈𝒜\textasciitilde{}|P(A)−Q(A)|} \tn % Row Count 1 (+ 1) % Row 1 \SetRowColor{white} \mymulticolumn{2}{x{5.377cm}}{D\textasciitilde{}H\textasciitilde{}(P,Q) = (1/√2)(∫(√(dP/dμ)−√(dQ/dμ))$^{\textrm{2}}$ dμ)\textasciicircum{}1/2\textasciicircum{}} \tn % Row Count 3 (+ 2) % Row 2 \SetRowColor{LightBackground} \mymulticolumn{2}{x{5.377cm}}{D\textasciitilde{}KL\textasciitilde{}(P||Q) = ∫ log(dP/dQ)dP if P≪Q; ∞ otherwise} \tn % Row Count 5 (+ 2) % Row 3 \SetRowColor{white} Expectation bound & ||E\textasciitilde{}P\textasciitilde{}{[}f{]} − E\textasciitilde{}Q\textasciitilde{}{[}f{]}|| ≤ 2D\textasciitilde{}H\textasciitilde{}(P,Q) (E\textasciitilde{}P\textasciitilde{}||f||$^{\textrm{2}}$+E\textasciitilde{}Q\textasciitilde{}||f||$^{\textrm{2}}$)\textasciicircum{}1/2\textasciicircum{} \tn % Row Count 8 (+ 3) \hhline{>{\arrayrulecolor{DarkBackground}}--} \end{tabularx} \par\addvspace{1.3em} % That's all folks \end{multicols*} \end{document}