- Commit
- 21b864b65b76846e3d18bdb8dba87a2cbc11e0dd
- Parent
- 12b23db03fe06c0261d967a8a2422e31a9cf9412
- Author
- Pablo <pablo-escobar@riseup.net>
- Date
Changed the notation for the Weyl group
Source code for my notes on representations of semisimple Lie algebras and Olivier Mathieu's classification of simple weight modules
Changed the notation for the Weyl group
2 files changed, 11 insertions, 11 deletions
Status | File Name | N° Changes | Insertions | Deletions |
Modified | sections/mathieu.tex | 2 | 1 | 1 |
Modified | sections/semisimple-algebras.tex | 20 | 10 | 10 |
diff --git a/sections/mathieu.tex b/sections/mathieu.tex @@ -108,7 +108,7 @@ parabolic and \(V_i\) is an irreducible cuspidal \(\mathfrak{p}_i\)-module then \(L_{\mathfrak{p}_1}(V_1) \cong L_{\mathfrak{p}_2}(V_2)\) if, and only if \(\mathfrak{p}_1 = \mathfrak{p}_2^w\) and \(V_1 \cong V_2^w\) for some \(w - \in W\). + \in \mathcal{W}\). \end{theorem} % TODO: Remark that the support of a simple weight module is always contained
diff --git a/sections/semisimple-algebras.tex b/sections/semisimple-algebras.tex @@ -2228,8 +2228,8 @@ is\dots \end{proof} \begin{definition} - We refer to the group \(W = \langle T_\alpha : \alpha \in \Delta^+ \rangle - \subset \operatorname{O}(\mathfrak{h}^*)\) as \emph{the Weyl group of + We refer to the group \(\mathcal{W} = \langle T_\alpha : \alpha \in \Delta^+ + \rangle \subset \operatorname{O}(\mathfrak{h}^*)\) as \emph{the Weyl group of \(\mathfrak{g}\)}. \end{definition} @@ -2243,7 +2243,7 @@ Indeed, the same argument leads us to the conclusion\dots highest weight \(\lambda\) are precisely the elements of the weight lattice \(P\) congruent to \(\lambda\) modulo the root lattice \(Q\) lying inside the convex hull of the image of \(\lambda\) under the action of the Weyl group - \(W\). + \(\mathcal{W}\). \end{theorem} Now the only thing we are missing for a complete classification is an existence @@ -2488,13 +2488,13 @@ semisimple \(\mathfrak{g}\). Namely\dots The proof of proposition~\ref{thm:verma-is-finite-dim} is very technical and we won't include it here, but the idea behind it is to show that the set of weights of \(\sfrac{M(\lambda)}{N(\lambda)}\) is stable under the natural -action of the Weyl group \(W\) in \(\mathfrak{h}^*\). One can then show that -the every weight of \(V\) is conjugate to a single dominant integral weight of -\(\sfrac{M(\lambda)}{N(\lambda)}\), and that the set of dominant integral -weights of such irreducible quotient is finite. Since \(W\) is finitely -generated, this implies the set of weights of the unique irreducible quotient -of \(M(\lambda)\) is finite. But each weight space is finite-dimensional. Hence -so is the irreducible quotient. +action of the Weyl group \(\mathcal{W}\) in \(\mathfrak{h}^*\). One can then +show that the every weight of \(V\) is conjugate to a single dominant integral +weight of \(\sfrac{M(\lambda)}{N(\lambda)}\), and that the set of dominant +integral weights of such irreducible quotient is finite. Since \(W\) is +finitely generated, this implies the set of weights of the unique irreducible +quotient of \(M(\lambda)\) is finite. But each weight space is +finite-dimensional. Hence so is the irreducible quotient. We refer the reader to \cite[ch. 21]{humphreys} for further details. What we are really interested in is\dots