- Commit
- 1261dc6376a8b86abc41efcfa3f7167c12b952f0
- Parent
- fb5df60b5bd44cfca0c193de5e961770ce4376a9
- Author
- Pablo <pablo-escobar@riseup.net>
- Date
Added minor clarifications
Source code for my notes on representations of semisimple Lie algebras and Olivier Mathieu's classification of simple weight modules
Added minor clarifications
1 file changed, 5 insertions, 9 deletions
Status | File Name | N° Changes | Insertions | Deletions |
Modified | sections/mathieu.tex | 14 | 5 | 9 |
diff --git a/sections/mathieu.tex b/sections/mathieu.tex @@ -114,7 +114,7 @@ % TODO: Remark that the support of a simple weight module is always contained % in a coset % TODO: Note that conditions (ii) and (iii) have special names -\begin{corollary}[Fernando] +\begin{corollary}[Fernando]\label{thm:cuspidal-mod-equivs} Let \(V\) be an irreducible weight \(\mathfrak{g}\)-module. The following conditions are equivalent. \begin{enumerate} @@ -256,9 +256,6 @@ \(\mathcal{M}^{\operatorname{ss}} \cong \operatorname{Ext}(V)\). \end{theorem} -% TODOO: This is already noted in a previous corollary by Fernando -% TODO: Note somewhere else that the support of a cuspidal module is an entire -% Q-coset \begin{proposition} Let \(V\) be a cuspidal representation of \(\mathfrak{g}\) and take any weight \(\lambda\) of \(V\). Then \(V \cong @@ -290,11 +287,10 @@ \] so that \(V_\mu\) is a \(C_{\mathcal{U}(\mathfrak{g})}(\mathfrak{h})\)-submodule of - \(\operatorname{Ext}(V)_\mu\). - Since \(V\) is cuspidal, \(\mu \in \lambda + Q = \operatorname{supp} V\) - implies \(V_\mu \ne 0\), and hence \(V_\mu = \operatorname{Ext}(V)_\mu\) -- - because \(\operatorname{Ext}(V)_\mu\) is an irreducible - \(C_{\mathcal{U}(\mathfrak{g})}(\mathfrak{h})\)-module. + \(\operatorname{Ext}(V)_\mu\). Since \(V\) is cuspidal, \(\mu \in \lambda + Q + = \operatorname{supp} V\) -- i.e. the third equivalence of + corollary~\ref{thm:cuspidal-mod-equivs} -- implies \(V_\mu \ne 0\), and hence + \(V_\mu = \operatorname{Ext}(V)_\mu\). \end{proof} \begin{theorem}[Mathieu]