- Commit
- 5f37c6db683aa4bb47a96693681a20cb5b111b6e
- Parent
- 07263fd14f21d83579955877e8000fcb333313ff
- Author
- Pablo <pablo-escobar@riseup.net>
- Date
Added further clarifications to the proof that V fits nicely inside Ext(V)
Source code for my notes on representations of semisimple Lie algebras and Olivier Mathieu's classification of simple weight modules
Added further clarifications to the proof that V fits nicely inside Ext(V)
1 file changed, 5 insertions, 5 deletions
Status | File Name | N° Changes | Insertions | Deletions |
Modified | sections/mathieu.tex | 10 | 5 | 5 |
diff --git a/sections/mathieu.tex b/sections/mathieu.tex @@ -265,14 +265,14 @@ (\operatorname{Ext}(V))[\lambda]\). \end{proposition} -% TODO: Do we need to use the fact that U(g) is netherian to conclude that V is -% the quotient of subsequent terms of a composition series? \begin{proof} Fix some coherent extension \(\mathcal{M}\) of \(V\), so that \(V\) is a subquotient of \(\mathcal{M}\). More precisely, since \(V\) is irreducible it - can be realized as the quotient of consecutive terms of a composition series - \(0 = \mathcal{M}_0 \subset \mathcal{M}_1 \subset \cdots \subset - \mathcal{M}_n = \mathcal{M}[\lambda]\). But + is a subquotient of \(\mathcal{M}[\lambda]\) -- its support is contained in + \(\lambda + Q\). Furtheremore, once again it follows from the irreducibility + of \(V\) that it can be realized as the quotient of consecutive terms of a + composition series \(0 = \mathcal{M}_0 \subset \mathcal{M}_1 \subset \cdots + \subset \mathcal{M}_n = \mathcal{M}[\lambda]\). But \[ (\operatorname{Ext}(V))[\lambda] \cong \mathcal{M}^{\operatorname{ss}}[\lambda]