From 95130401cd6e73c410d112d46541a9026ad83752 Mon Sep 17 00:00:00 2001 From: Nathaniel Wesley Filardo Date: Thu, 2 Apr 2015 00:57:18 -0400 Subject: [PATCH] Improve cross-referencing to examples in ctcheat --- ctcheat.tex | 55 ++++++++++++++++++++++++++++++++++------------------- 1 file changed, 35 insertions(+), 20 deletions(-) diff --git a/ctcheat.tex b/ctcheat.tex index 2de1e66..c544bf1 100644 --- a/ctcheat.tex +++ b/ctcheat.tex @@ -103,6 +103,10 @@ \newcommand{\xrdefn}[1]{\ref{\forcsvlist{\xrdefnhelper}{#1}}} \newcommand{\hrdefn}[2][]{\ifstrempty{#1}{\hyperref[defn:#2]{#2}[\ref{defn:#2}]} {\hyperref[defn:#1]{#2}[\ref{defn:#1}]}} + +\newcommand\xrexhelper[1]{ex:#1} +\newcommand{\xrex}[1]{EX: \ref{\forcsvlist{\xrexhelper}{#1}}} + \begin{document} %>>> % Intro <<< @@ -218,7 +222,7 @@ quantified formula. % $C$ is a \defn{coseparator} if $\forall_{f,g : B \to A} f \ne g \Rightarrow \exists_{h : A \to C} . h \circ f \ne h \circ g$. (\S7.17) - (Contrast monomorphism.) + (Contrast \hrdefn{monomorphism}.) % \paragraph{} % % @@ -269,7 +273,7 @@ quantified formula. % $S$ is a \defn{separator} if $\forall_{f,g : A \to B} f \ne g \Rightarrow \exists_{h : S \to A} . f \circ h \ne g \circ h$. (\S7.10) - (Contrast epimorphism.) + (Contrast \hrdefn{epimorphism}.) $S$ is a separator iff $\mbox{hom}(S,-)$ is faithful. (\S7.12) \paragraph{} @@ -286,7 +290,7 @@ quantified formula. \paragraph{} % An object that is both initial and terminal is called a \defn{zero}. - (\S7.7) + (\S7.7) \xrex{mon0} % >>> \section{Arrow Properties} % <<< @@ -298,6 +302,7 @@ quantified formula. Z & Q \ar@{..>}[l]^u & B \ar[l]^q \ar@/^1pc/[ll]^{z} & A \ar@<1ex>[l]^f \ar@<-1ex>[l]_g }\] Coequalizers are essentially unique (\S7.70.1) and epic (\S7.71,\S7.75.2). + \xrex{setcoeq} \paragraph{} % @@ -307,7 +312,7 @@ quantified formula. \[\xymatrix{\forall_{i,j} ie = je \Rightarrow i = j & A \ar@{->>}[r]^e & B \ar@<1ex>[r]^{i} \ar@<-1ex>[r]_j & C} \] % If $f$ and $g$ are epis, then so is $g \circ f$; if $g \circ f$ is epi, - then so is $g$. (\S7.41) + then so is $g$. (\S7.41) \xrex{setmonepi} \paragraph{} % @@ -317,6 +322,7 @@ quantified formula. Z \ar@{..>}[r]^u \ar@/_1pc/[rr]^{z} & E \ar[r]^e & A \ar@<1ex>[r]^f \ar@<-1ex>[r]_g & B \\ }\] Equalizers are essentially unique (\S7.53) and monic (\S7.56,\S7.59.2). + \xrex{seteq} \paragraph{} % @@ -365,11 +371,11 @@ quantified formula. \[\xymatrix{\forall_{i,j} mi = mj \Rightarrow i = j & C \ar@<1ex>[r]^{i} \ar@<-1ex>[r]_j & A \ar@{{ >}->}[r]^m & B} \] If $f$ and $g$ are monos, then so is $g \circ f$; if $g \circ f$ is mono, then so is $f$. (\S7.34) Objects with monomorphisms to $X$ are called - \defn{subobjects} of $X$ (Awodey:D5.1). + \defn{subobjects} of $X$ (Awodey:D5.1). \xrex{setmonepi} \paragraph{} % - A \defn{point} (Awodey:p32) of $C$ is any $c : 1 \to C$. + A \defn{point} (Awodey:p32) of $C$ is any $c : 1 \to C$. \xrex{monpt} \paragraph{} % @@ -394,7 +400,7 @@ quantified formula. % Several morphism properties combine in useful ways: \begin{itemize} - \item mono, epi $\Rightarrow$ \defn{bimorphism} (\S7.49) + \item mono, epi $\Rightarrow$ \defn{bimorphism} (\S7.49) \xrex{monbi} \item section $\Rightarrow$ regular mono (\S7.35, \S7.59.1) \item regular mono $\Rightarrow$ extremal mono (\S7.59.2, \S7.63) \item retraction $\Rightarrow$ epi (\S7.42) @@ -659,6 +665,9 @@ quantified formula. % >>> \section{Adjoints and Adjoint Situations} % <<< +\label{sec:adj} + +Be sure to see \autoref{sec:adjex} for examples. \subsection{Joy Approach} @@ -795,33 +804,39 @@ quantified formula. \subsection{$\mathbf{Set}$} - \paragraph{} Epic is surjective, monic is injective. + \paragraph{}\label{ex:setmonepi} + % + \hrdefn[epic]{Epic} is surjective, \hrdefn{monic} is injective. - \paragraph{} - Coequalizers correspond to equivalence classes (\S7.69.1): Let $\sim$ be - {\em the smallest} eq. rel. s.t. $\forall_{a \in A} f(a) \sim g(a)$; - then $(Q,q) = (B/\sim, b \mapsto \brak{b}_\sim)$ is a coequalizer of $f$ - and $g$. + \paragraph{}\label{ex:setcoeq} + % + \hrdefn[coequalizer]{Coequalizers} correspond to equivalence classes + (\S7.69.1): Let $\sim$ be {\em the smallest} eq. rel. s.t. $\forall_{a \in + A} f(a) \sim g(a)$; then $(Q,q) = (B/\sim, b \mapsto \brak{b}_\sim)$ is a + coequalizer of $f$ and $g$. - \paragraph{} - Equalizers: $(E,e) = (\set{x \mid f(x) = g(x)} \subseteq X, \subseteq)$. + \paragraph{}\label{ex:seteq} + % + \hrdefn[equalizer]{Equalizers}: $(E,e) = (\set{x \mid f(x) = g(x)} \subseteq X, \subseteq)$. \subsection{$\mathbf{Mon}$} - \paragraph{} + \paragraph{}\label{ex:monbi} % \hrdefn[bimorphism]{Bimorphisms} are not isos: ($(\mathbf{N},+,0) \to (\mathbf{Z},+,0)$). (Pierce:\S1.6.3) - \paragraph{} + \paragraph{}\label{ex:mon0} % - $(\set{*},\cdot,*)$ is a (the) zero. + $(\set{*},\cdot,*)$ is a (the) \hrdefn{zero}. - \paragraph{} + \paragraph{}\label{ex:monpt} % - Each monoid $M$ has only one point, $1 \to M$. + Each monoid $M$ has only one \hrdefn{point}, $1 \to M$. \subsection{Adjoint Situations and Monads} + \label{sec:adjex} + Defintitons in \autoref{sec:adj}. \paragraph{} % -- 2.50.1