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authorFranciszek Malinka <franciszek.malinka@gmail.com>2022-06-28 18:28:29 +0200
committerFranciszek Malinka <franciszek.malinka@gmail.com>2022-06-28 18:28:29 +0200
commit8c3772288630df347539eadde88dc22cc4ef2af0 (patch)
treedb302d86910ef1a596be3686f4fedfa45018df6c
parent22dfe4dade829c5b9fc1f8928f0c78ce99084e19 (diff)
Nowe rzeczy, wstep do teorii kategorii
-rw-r--r--.gitignore5
-rw-r--r--lic_malinka.bib (renamed from licmalinka.bib)9
-rw-r--r--lic_malinka.pdfbin398521 -> 404331 bytes
-rw-r--r--lic_malinka.tex85
-rw-r--r--update-pdf.sh27
5 files changed, 84 insertions, 42 deletions
diff --git a/.gitignore b/.gitignore
index a53d1a8..c8332b7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,7 @@
lic_malinka.*
+szkola-orlow*
!lic_malinka.tex
-!lic_malinka.pdf \ No newline at end of file
+!lic_malinka.pdf
+!lic_malinka.bib
+
diff --git a/licmalinka.bib b/lic_malinka.bib
index 4c4c881..34451a7 100644
--- a/licmalinka.bib
+++ b/lic_malinka.bib
@@ -7,4 +7,11 @@
author={Hodges, Wilfrid},
year={1993},
collection={Encyclopedia of Mathematics and its Applications}
-} \ No newline at end of file
+}
+@book{maclane_1978,
+ title={Categories for the Working Mathematics},
+ DOI={10.1007/978-1-4757-4721-8},
+ publisher={Springer New York, NY},
+ author={Saunders Mac Lane},
+ year={1978},
+}
diff --git a/lic_malinka.pdf b/lic_malinka.pdf
index 64f797a..a584720 100644
--- a/lic_malinka.pdf
+++ b/lic_malinka.pdf
Binary files differ
diff --git a/lic_malinka.tex b/lic_malinka.tex
index 9cce430..bc4d53b 100644
--- a/lic_malinka.tex
+++ b/lic_malinka.tex
@@ -1,9 +1,9 @@
-\documentclass[11pt, a4paper, final]{amsart}
+\documentclass[12pt, a4paper, final]{amsart}
\setlength{\emergencystretch}{2em}
\usepackage[utf8]{inputenc}
\usepackage[backend=biber]{biblatex}
-\addbibresource{licmalinka.bib}
+\addbibresource{lic_malinka.bib}
\usepackage[T1]{fontenc}
\usepackage{mathtools}
@@ -11,6 +11,7 @@
\microtypecontext{spacing=nonfrench}
% \usepackage[utf8]{inputenc}
+
\usepackage{amsfonts}
\usepackage{amsmath}
\usepackage{amssymb}
@@ -65,6 +66,8 @@
\DeclareMathOperator{\id}{{id}}
\DeclareMathOperator{\lin}{{Lin}}
\DeclareMathOperator{\Th}{{Th}}
+\DeclareMathOperator{\Obj}{{Obj}}
+\DeclareMathOperator{\Mor}{{Mor}}
\newtheorem{theorem}{Theorem}
\numberwithin{theorem}{section}
@@ -353,6 +356,49 @@
it's much easier to work with basic open sets rather than any open
sets.
+ \subsection{Category theory}
+
+ In this section we will give a short introduction to the notions of
+ category theory that will be necessary to generalize the key result of the
+ paper.
+
+ We will use a standard notation. If the reader is interested in detailed
+ introduction to the category theory, then it's recommended to take a look
+ at \cite{maclane_1978}. Here we will shortly describe the standard notation.
+
+ A \emph{category} $\cC$ consists of the collection of objects (denoted as
+ $\Obj(\cC)$, but most often simply as $\cC$) and collection of \emph{morphisms}
+ $\Mor(A, B)$ between each pair of objects $A, B\in \cC$. We require that
+ for each morphisms $f\colon B\to C$, $g\colon A\to B$ there is a morphism
+ $f\circ g\colon A\to C$. For every $A\in\cC$ there is an
+ \emph{identity morphism} $\id_A$ such that for any morphism $f\in \Mor(A, B)$
+ it follows that $f\circ id_A = \id_B \circ f$.
+
+ A \emph{functor} is a ``homeomorphism`` of categories. $F\colon\cC\to\cD$ is a functor
+ from category $\cC$ to category $\cD$ if it associates each object $A\in\cC$
+ with an object $F(A)\in\cD$, associates each morphism $f\colon A\to B$ in
+ $\cC$ with a morphism $F(f)\colon F(A)\to F(B)$. We also require that
+ $F(\id_A) = \id_{F(A)}$ and that for any (compatible) morphisms $f, g$ in $\cC$
+ $F(f\circ g) = F(f) \circ F(g)$.
+
+ Notion that will be very important for us is a ``morphism of functors``
+ which is called \emph{natural transformation}.
+ \begin{definition}
+ Let $F, G$ be functors between the categories $\cC, \cD$. A \emph{natural
+ transformation}
+ $\tau$ is function that assigns to each object $A$ of $\cC$ a morphism $\tau_A$
+ in $\Mor(F(A), G(A))$ such that for every morphism $f\colon A\to B$ in $\cC$
+ the following diagram commutes:
+
+ \begin{center}
+ \begin{tikzcd}
+ A \arrow[d, "f"] & F(A) \arrow[r, "\tau_A"] \arrow[d, "F(f)"] & G(A) \arrow[d, "G(f)"] \\
+ B & F(B) \arrow[r, "\tau_B"] & G(B) \\
+ \end{tikzcd}
+ \end{center}
+ \end{definition}
+
+
\section{Fraïssé classes}
In this section we will take a closer look at classes of finitely
@@ -701,12 +747,6 @@
\section{Conjugacy classes in automorphism groups}
- TODO:
- \begin{itemize}
- \item w głównym dowodzie mogę użyć wprost AP, nie muszę tego uzasadniać
- jeszcze raz.
- \end{itemize}
-
Let $M$ be a countable $L$-structure. We define a topology on the $G=\Aut(M)$:
for any finite function $f\colon M\to M$ we have a basic open set
$[f]_{G} = \{g\in G\mid f\subseteq g\}$.
@@ -925,15 +965,34 @@
\subsection{Properties of the generic automorphism}
+ Let $\cC$ be a Fraïssé class in a finite relational language $L$ with
+ weak Hrushovski property. Let $\cH$ be the Fraïssé class of the $L$-structures
+ with additional automorphism symbol. Let $\Gamma = \Flim(\cC)$.
+
+ % \begin{proposition}
+ % Let $\sigma$ be the generic automorphism of the random graph $\FrGr$. Then
+ % the graph induced by the set of the fixed points of $\sigma$ is isomorphic
+ % to $\FrGr$.
+ % \end{proposition}
+ %
+ % \begin{proof}
+ % Let $F = \{v\in\FrGr\mid \sigma(v) = v\}$. It suffices to show that $F$ is
+ % infinite and has the random graph property.
+ % \end{proof}
\begin{proposition}
- Let $\sigma$ be the generic automorphism of the random graph $\FrGr$. Then
- the graph induced by the set of the fixed points of $\sigma$ is isomorphic
- to $\FrGr$.
+ Let $\sigma$ be the generic automorphism of $\Gamma$. Then the set
+ of fixed points of $\sigma$ is isomorphic to $\Gamma$.
\end{proposition}
\begin{proof}
- Let $F = \{v\in\FrGr\mid \sigma(v) = v\}$. It suffices to show that $F$ is
- infinite and has the random graph property.
+ Let $S = \{x\in \Gamma\mid \sigma(x) = x\}$.
+ First we need to show that it is an infinite. By the theorem \ref{theorem:generic_aut_general}
+ we know that $(\Gamma, \sigma)$ is the Fraïssé limit of $\cH$, thus we
+ can embedd finite $L$-structures of any size with identity as an
+ automorphism of the structure into $(\Gamma, \sigma)$. Thus $S$ has to be
+ infinite. Also, the same argument shows that the age of the structure is
+ exactly $\cC$. It is weakly ultrahomogeneous, also by the fact that
+ $(\Gamma, \sigma)$ is in $\cH$.
\end{proof}
\printbibliography
\end{document}
diff --git a/update-pdf.sh b/update-pdf.sh
deleted file mode 100644
index f342079..0000000
--- a/update-pdf.sh
+++ /dev/null
@@ -1,27 +0,0 @@
-if [[ $# != 1 ]]
-then
- echo "Usage: $0 [.tex file]"
- exit 1
-fi
-
-PRACA=$1
-if ! [[ -f $PRACA ]]
-then
- echo "No such file: $PRACA"
- exit 1
-fi
-
-threshold=1
-while true
-do
- if (($(date +"%s")- $(stat --format="%Y" $PRACA) < $threshold))
- then
- echo "updating"
- pdflatex $PRACA
- biber $PARACA
- pdflatex $PRACA
- pdflatex $PRACA
- else
- sleep 0.2
- fi
-done