change notation for anamorphisms

This commit is contained in:
Leon Vatthauer 2024-03-06 14:11:27 +01:00
parent b4cb17e52b
commit e11960fa58
Signed by: leonv
SSH key fingerprint: SHA256:G4+ddwoZmhLPRB1agvXzZMXIzkVJ36dUYZXf5NxT+u8
2 changed files with 53 additions and 12 deletions

View file

@ -99,6 +99,8 @@
\usepackage{noto-mono}
\usepackage{mathpazo}
\usepackage{unicode-math}
\usepackage{mathrsfs}
\usepackage[colorinlistoftodos,prependcaption,textsize=tiny]{todonotes}
\usepackage{xargs}
@ -106,6 +108,43 @@
%\usepackage{fontspec}
%\setmonofont{Noto Sans Mono}
\usepackage{pict2e}
% \newcommand{\lbparen}{%
% \mathopen{%
% \sbox0{$()$}%
% \setlength{\unitlength}{\dimexpr\ht0+\dp0}%
% \raisebox{-\dp0}{%
% \begin{picture}(.32,1)
% \linethickness{\fontdimen8\textfont3}
% \roundcap
% \put(0,0){\raisebox{\depth}{$($}}
% \polyline(0.32,0)(0.1,0)(0.1,1)(0.32,1)
% \end{picture}%
% }%
% }%
% }
% \newcommand{\rbparen}{%
% \mathclose{%
% \sbox0{$()$}%
% \setlength{\unitlength}{\dimexpr\ht0+\dp0}%
% \raisebox{-\dp0}{%
% \begin{picture}(.32,1)
% \linethickness{\fontdimen8\textfont3}
% \roundcap
% \put(0.02,0){\raisebox{\depth}{$)$}}
% \polyline(0.1,0)(0.32,0)(0.32,1)(0.1,1)
% \end{picture}%
% }%
% }%
% }
\newcommand{\lbparen}{}
% https://unicodeplus.com/U+3016
\newcommand{\rbparen}{}
% category C
\newcommand*{\C}{\ensuremath{\mathscr{C}}}
\newcommand*{\D}{\ensuremath{\mathscr{D}}}
@ -142,7 +181,7 @@
}
}
% terminal coalgebra
\newcommand*{\coalg}[1]{\ensuremath{\llbracket #1 \rrbracket}}
\newcommand*{\coalg}[1]{\ensuremath{\lbparen#1\rbparen}}
\begin{document}
\pagestyle{plain}
@ -168,6 +207,7 @@ Erlangen, \today{} \rule{7cm}{1pt}\\
\newcommandx{\info}[2][1=]{\todo[inline,linecolor=OliveGreen,backgroundcolor=OliveGreen!25,bordercolor=OliveGreen,#1]{#2}}
\newcommandx{\improvement}[2][1=]{\todo[inline,linecolor=Plum,backgroundcolor=Plum!25,bordercolor=Plum,#1]{#2}}
% for creating custom labels like (Fixpoint)
\makeatletter
\newcommand{\customlabel}[2]{%

View file

@ -357,11 +357,12 @@ Finality of the coalgebras $(DX, out : DX \rightarrow X + DX)_{X \in \obj{\C}}$
\arrow["out", from=3-1, to=3-5]
\arrow["{id \times out}", from=1-1, to=1-2]
\arrow["dstl", from=1-2, to=1-3]
\arrow["{\coalg{-}}", dashed, from=1-1, to=3-1]
\arrow["{\coalg{\text{-}}}", dashed, from=1-1, to=3-1]
\arrow["{f \times g + id}", from=1-3, to=1-5]
\arrow["{id + \coalg{-}}", dashed, from=1-5, to=3-5]
\arrow["{id + \coalg{\text{-}}}", dashed, from=1-5, to=3-5]
\end{tikzcd}\]
We write $\coalg{-}$ to abbreviate the used coalgebra, i.e.\ in this diagram $\coalg{-} = \coalg{(f\times g + id) \circ dstl \circ (id \times out)}$
We write $\coalg{\text{-}}$ to abbreviate the used coalgebra, i.e.\ in the previous diagram
\[\coalg{\text{-}} = \coalg{(f\times g + id) \circ dstl \circ (id \times out)}.\]
Next we check the strength laws:
\begin{itemize}
@ -371,8 +372,8 @@ Finality of the coalgebras $(DX, out : DX \rightarrow X + DX)_{X \in \obj{\C}}$
{1 \times DX} \& {1 \times X + DX} \& {1 \times X + 1 \times DX} \& {X + 1 \times DX} \\
DX \&\&\& {X + DX}
\arrow["out", from=2-1, to=2-4]
\arrow["{\coalg{-}}", dashed, from=1-1, to=2-1]
\arrow["{id + \coalg{-}}", from=1-4, to=2-4]
\arrow["{\coalg{\text{-}}}", dashed, from=1-1, to=2-1]
\arrow["{id + \coalg{\text{-}}}", from=1-4, to=2-4]
\arrow["{id \times out}", from=1-1, to=1-2]
\arrow["dstl", from=1-2, to=1-3]
\arrow["{\pi_2 + id}", from=1-3, to=1-4]
@ -396,11 +397,11 @@ Finality of the coalgebras $(DX, out : DX \rightarrow X + DX)_{X \in \obj{\C}}$
{X \times DDY} \& {X \times (DY + DDY)} \& {X \times DY + X \times DDY} \\
\&\& {X \times Y + X \times DDY} \\
{D(X\times Y)} \&\& {X \times Y + D(X \times Y)}
\arrow["{\coalg{-}}", dashed, from=1-1, to=3-1]
\arrow["{\coalg{\text{-}}}", dashed, from=1-1, to=3-1]
\arrow["{id \times out}", from=1-1, to=1-2]
\arrow["dstl", from=1-2, to=1-3]
\arrow["out", from=3-1, to=3-3]
\arrow["{id + \coalg{-}}"', from=2-3, to=3-3]
\arrow["{id + \coalg{\text{-}}}"', from=2-3, to=3-3]
\arrow["{[ (id + (id \times now)) \circ dstl \circ (id \times out) , i_2 ]}"', from=1-3, to=2-3]
\end{tikzcd}\]
\item[\ref{S4}] To show $D\alpha \circ \tau = \tau \circ (id \times \tau) \circ \alpha$ by coinduction we take the coalgebra:
@ -409,9 +410,9 @@ Finality of the coalgebras $(DX, out : DX \rightarrow X + DX)_{X \in \obj{\C}}$
{(X \times Y) \times DZ} \& {(X \times Y) \times (Z+ DZ)} \& {(X\times Y) \times Z + (X \times Y) \times DZ} \\
\&\& {X \times Y \times Z + (X \times Y) \times DZ} \\
{D(X \times Y \times Z)} \&\& {X \times Y \times Z + D(X \times Y \times Z)}
\arrow["{\coalg{-}}", dashed, from=1-1, to=3-1]
\arrow["{\coalg{\text{-}}}", dashed, from=1-1, to=3-1]
\arrow["out", from=3-1, to=3-3]
\arrow["{id +\coalg{-}}"', from=2-3, to=3-3]
\arrow["{id +\coalg{\text{-}}}"', from=2-3, to=3-3]
\arrow["{id \times out}", from=1-1, to=1-2]
\arrow["dstl", from=1-2, to=1-3]
\arrow["{\langle \pi_1 \circ \pi_1 , \langle \pi_2 \circ \pi_1 , \pi_2 \rangle \rangle + id}"', from=1-3, to=2-3]
@ -451,8 +452,8 @@ To prove that $\mathbf{D}$ is commutative we will use another proof principle pr
\arrow["out", from=2-1, to=2-4]
\arrow["out", from=1-1, to=1-2]
\arrow["{[ [ i_1 , h ] , i_2 ]}", from=1-2, to=1-4]
\arrow["{id + \coalg{-}}", from=1-4, to=2-4]
\arrow["{\coalg{-}}", dashed, from=1-1, to=2-1]
\arrow["{id + \coalg{\text{-}}}", from=1-4, to=2-4]
\arrow["{\coalg{\text{-}}}", dashed, from=1-1, to=2-1]
\end{tikzcd}\]
\end{proof}