- Commit
- 838b421afaf9aa157d877619768ebcdd903fb812
- Parent
- 9f03a21b2f8b1e178d0a0f11394d696a686d98de
- Author
- Pablo <pablo-pie@riseup.net>
- Date
Added names to the most important relations we derrive
My M2 Memoire on mapping class groups & their representations
Added names to the most important relations we derrive
2 files changed, 5 insertions, 7 deletions
Status | File Name | N° Changes | Insertions | Deletions |
Modified | sections/presentation.tex | 8 | 3 | 5 |
Modified | sections/twists.tex | 4 | 2 | 2 |
diff --git a/sections/presentation.tex b/sections/presentation.tex @@ -8,9 +8,7 @@ intuition behind them, culminating in the statement of a presentation for geometry of curves in \(\Sigma_g\) -- see Theorem~\ref{thm:wajnryb-presentation}. -We start by the so called \emph{lantern relation}. - -\begin{fundamental-observation} +\begin{fundamental-observation}[Lantern relation] Let \(\Sigma_0^4\) be the surface the of genus \(0\) with \(4\) boundary components and \(\alpha, \beta, \gamma, \delta_1, \ldots, \delta_4 \subset \Sigma_0^4\) be as in Figure~\ref{fig:latern-relation}. Consider the @@ -320,7 +318,7 @@ not isotopic \emph{through symmetric homeomorphisms}. Birman-Hilden \cite[Section~9.4]{farb-margalit}. \end{observation} -\begin{fundamental-observation} +\begin{fundamental-observation}[$k$-chain relations] The Birman-Hilden isomorphism \(\SMod(\Sigma_\ell^1) \isoto \Mod(\Sigma_{0, 2\ell+1}^1)\) takes the twists \(\tau_\delta \in \SMod(\Sigma_\ell^1)\) about the boundary \(\delta = \partial \Sigma_\ell^1\) to \(\tau_{\bar\delta}^2 \in @@ -368,7 +366,7 @@ to obtain other relations. Since \(\iota\) has \(2g + 2\) fixed points in 2})\). \end{theorem} -\begin{fundamental-observation} +\begin{fundamental-observation}[Hyperelliptic relations] Let \(\alpha_1, \ldots, \alpha_{2g}, \delta \subset \Sigma_g\) be as in Figure~\ref{fig:hyperellipitic-relations}. Then \begin{equation}\label{eq:hyperelliptic-eq}
diff --git a/sections/twists.tex b/sections/twists.tex @@ -161,7 +161,7 @@ too. f^{-1}\). \end{observation} -\begin{observation} +\begin{observation}[Disjointness relations] Given \(f \in \Mod(\Sigma)\), \([f, \tau_\alpha] = 1 \iff f \cdot [\alpha] = [\alpha]\). In particular, \([\tau_\alpha, \tau_\beta] = 1\) for \(\alpha\) and \(\beta\) disjoint. @@ -174,7 +174,7 @@ too. [\alpha] = [\beta]\) and then apply Observation~\ref{ex:conjugate-twists}. \end{observation} -\begin{fundamental-observation}\label{ex:braid-relation} +\begin{fundamental-observation}[Braid relations]\label{ex:braid-relation} Given \(\alpha, \beta \subset \Sigma\) with \(\#(\alpha \cap \beta) = 1\), it is not hard to check that \(\tau_\beta \tau_\alpha \cdot [\beta] = [\alpha]\). From Observation~\ref{ex:conjugate-twists} we then get