- Commit
- 6078bdea5d725c15f9ebbc63fdad2d5f3fb3dba3
- Parent
- ab471a10bb3bb1227bb0f20142f1a887982387af
- Author
- Pablo <pablo-pie@riseup.net>
- Date
Removed the used of \dots
My M2 Memoire on mapping class groups & their representations
Removed the used of \dots
4 files changed, 19 insertions, 16 deletions
Status | File Name | N° Changes | Insertions | Deletions |
Modified | sections/introduction.tex | 6 | 3 | 3 |
Modified | sections/presentation.tex | 7 | 4 | 3 |
Modified | sections/representations.tex | 5 | 2 | 3 |
Modified | sections/twists.tex | 17 | 10 | 7 |
diff --git a/sections/introduction.tex b/sections/introduction.tex @@ -71,7 +71,7 @@ homeomorphisms. \end{figure} By splitting \(\Sigma\) across curves \(\alpha, \alpha' \subset \Sigma\) -crossing once, we can also show\dots +crossing once, we can also show the following result. \begin{observation}\label{ex:change-of-coordinates-crossing} Let \(\alpha, \beta, \alpha', \beta' \subset \Sigma\) be nonseparating curves @@ -88,7 +88,7 @@ orientation-preserving homeomorphisms of \(\Sigma\) fixing each point in rich geometry, but its algebraic structure is often regarded as too complex to tackle. More importantly, all of this complexity is arguably unnecessary for most topological applications, in the sense that usually we are only really -interested in considering \emph{homeomorphisms up to isotopy}. For example\dots +interested in considering \emph{homeomorphisms up to isotopy}. For example: \begin{enumerate} \item Isotopic \(\phi \simeq \psi \in \Homeo^+(\Sigma, \partial \Sigma)\) determine the same application \(\phi_* = \psi_* : \pi_1(\Sigma, x) \to @@ -116,7 +116,7 @@ hand. \] \end{definition} -There are many variations of Definition~\ref{def:mcg}. For example\dots +There are many variations of Definition~\ref{def:mcg}. \begin{observation}\label{ex:action-on-punctures} Any \(\phi \in \Homeo^+(\Sigma, \partial \Sigma)\) extends uniquely to a
diff --git a/sections/presentation.tex b/sections/presentation.tex @@ -64,7 +64,8 @@ Theorem~\ref{thm:wajnryb-presentation}. We may exploit different embeddings \(\Sigma_0^4 \hookrightarrow \Sigma\) and their corresponding inclusion homomorphisms \(\Mod(\Sigma_0^4) \to \Mod(\Sigma)\) to obtain interesting relations between the corresponding Dehn -twists in \(\Mod(\Sigma)\). For example\dots +twists in \(\Mod(\Sigma)\). For example, the lantern relation can be used to +compute \(\Mod(\Sigma_g^b)^\ab\) for \(g \ge 3\). \begin{proposition}\label{thm:trivial-abelianization} The Abelianization \(\Mod(\Sigma_g^b)^\ab = @@ -106,7 +107,7 @@ twists in \(\Mod(\Sigma)\). For example\dots To get extra relations we need to investigate certain branched covers \(\Sigma \to \mathbb{D}^2 \setminus \{x_1, \ldots, x_r\}\), as well as the relationship between \(\Mod(\Sigma)\) and \(\Mod(\mathbb{D}^2 \setminus \{x_1, \ldots, -x_r\})\). This is what is known as\dots +x_r\})\). This is what is known as \emph{the Birman-Hilden theorem}. \section{The Birman-Hilden Theorem}\label{birman-hilden} @@ -174,7 +175,7 @@ sequence \end{tikzcd} \end{center} for \(\Homeo^+(\mathbb{D}^2, \mathbb{S}^1)\) is contractible by -Observation~\ref{ex:alexander-trick}. In other words\dots +Observation~\ref{ex:alexander-trick}. We thus obtain the following result. \begin{proposition} The map \(\operatorname{push} : B_n \to \Mod(\Sigma_{0, n}^1)\) is a group
diff --git a/sections/representations.tex b/sections/representations.tex @@ -10,8 +10,7 @@ Historically, these relations have been exploited by Funar \cite{funar}, Franks-Handel \cite{franks-handel} and others to establish the triviality of low-dimensional representations, culminating in Korkmaz' \cite{korkmaz} recent classification of representations of dimension \(n \le 2 g\) for \(g \ge 3\). -The goal of this chapter is to provide a concise account of Korkmaz' results, -starting by\dots +The goal of this chapter is to provide a concise account of Korkmaz' results. \begin{theorem}[Korkmaz]\label{thm:low-dim-reps-are-trivial} Let \(\Sigma_g^b\) be the compact surface of genus \(g \ge 1\) with \(b\) @@ -476,7 +475,7 @@ Unfortunately, the limited scope of these master thesis does not allow us to dive into the proof of Theorem~\ref{thm:reps-of-dim-2g-are-symplectic}. The heart of this proof lies in a result about representations of the product \(B_3^n = B_3 \times \cdots \times B_3\), which Korkmaz refers to as \emph{the -main lemma}. Namely\dots +main lemma}. \begin{lemma}[Korkmaz' main lemma]\label{thm:main-lemma} Given \(i = 1, \ldots, n\), denote by
diff --git a/sections/twists.tex b/sections/twists.tex @@ -14,7 +14,8 @@ Observation~\ref{ex:torus-mcg}: by cutting across curves and arcs, we can always decompose a surface into copies of \(\mathbb{D}^2\) and \(\mathbb{D}^2 \setminus \{0\}\). Observation~\ref{ex:alexander-trick} and Observation~\ref{ex:mdg-once-punctured-disk} then imply the triviality of -mapping classes fixing such arcs and curves. Formally, this translates to\dots +mapping classes fixing such arcs and curves. Formally, this translates to the +following result. \begin{proposition}[Alexander method]\label{thm:alexander-method} Let \(\alpha_1, \ldots, \alpha_n \subset \Sigma\) be essential simple closed @@ -216,7 +217,7 @@ too. \] \end{observation} -A perhaps less obvious fact about Dehn twists is\dots +A perhaps less obvious fact about Dehn twists is the following. \begin{theorem}\label{thm:mcg-is-fg} Let \(\Sigma_{g, r}^b\) be the orientable surface of genus \(g \ge 1\) with @@ -271,7 +272,8 @@ fibration\footnote{See \cite[Chapter~4]{hatcher} for a reference.} & & \phi & \mapsto & [\phi(x_1), \ldots, \phi(x_n)] \end{array} \] -and its long exact sequence in homotopy we then get\dots +and its long exact sequence in homotopy we then obtain the following +fundamental result. \begin{theorem}[Birman exact sequence]\label{thm:birman-exact-seq} Suppose \(\pi_1(\Homeo^+(\Sigma, \partial \Sigma), 1) = 1\). Then there is an @@ -310,7 +312,8 @@ x_{\sigma(i)}\) for some \(\sigma \in S_n\). The element mapping class that ``\emph{pushes} a neighborhood of \(x_{\sigma(i)}\) towards \(x_i\) along the curve \(\alpha_i^{-1}\),'' as shown in Figure~\ref{fig:push-map} for the case \(n = 1\). Indeed, this goes to -show\dots +show \(\operatorname{push}([\alpha])\) can be descrived as a product of Dehn +twists. \begin{fundamental-observation}\label{ex:push-simple-loop} Using the notation of Figure~\ref{fig:push-map}, @@ -346,7 +349,7 @@ to apply the following lemma from geometric group theory. \end{lemma} We are interested, of course, in the group \(G = \PMod(\Sigma_{g, r}^b)\). As -for the graph \(\Gamma\), we consider\dots +for the the role of \(\Gamma\), we consider the following graph. \begin{definition} The \emph{modified graph of nonseparating curves @@ -397,7 +400,7 @@ In other words, given simple closed curves \(\alpha, \beta \subset \Sigma_{g, r}\), we can find closed \(\alpha = \alpha_1, \alpha_2, \ldots, \alpha_n = \beta\) in \(\Sigma_{g, r}\) with \(\alpha_i\) disjoint from \(\alpha_{i+1}\). Now if \(\alpha\) and \(\beta\) are nonseparating, by inductively adjusting -this sequence of curves we then get\dots +this sequence of curves we obtain the following corollary. \begin{corollary}\label{thm:mofied-graph-is-connected} If \(g \ge 2\) then both \(\mathcal{N}(\Sigma_{g, r})\) and @@ -436,7 +439,7 @@ Theorem~\ref{thm:mcg-is-fg}. \begin{figure}[ht] \centering - \includegraphics[width=.55\linewidth]{images/torus-mcg-generators.eps} + \includegraphics[width=.5\linewidth]{images/torus-mcg-generators.eps} \caption{The curves $\alpha$ and $\beta$ whose Dehn twists generate $\Mod(\mathbb{T}^2)$ and $\Mod(\Sigma_{1, 1})$.} \label{fig:torus-mcg-generators}