- Commit
- c20073ceafbc1d62e31e254d8471d97c9f45e385
- Parent
- 7cda57c57ff475e2085251b28c324b286d7ab8f2
- Author
- Pablo <pablo-escobar@riseup.net>
- Date
Edited some TODO items
Source code for my notes on representations of semisimple Lie algebras and Olivier Mathieu's classification of simple weight modules
Edited some TODO items
1 file changed, 11 insertions, 8 deletions
Status | File Name | N° Changes | Insertions | Deletions |
Modified | sections/mathieu.tex | 19 | 11 | 8 |
diff --git a/sections/mathieu.tex b/sections/mathieu.tex @@ -216,6 +216,8 @@ the following definition. \end{definition} % TODO: Define nilpotent algebras beforehand +% TODO: Define the nilradical in the introduction and state that the quotient +% of an alebra by its nilradical is reductive % TODO: State the universal property of quotients in the introduction Parabolic subalgebras thus give us a process for constructing weight \(\mathfrak{g}\)-modules from representations of smaller (parabolic) @@ -290,7 +292,7 @@ We should point out that the relationship between irreducible weight cuspidal \(\mathfrak{p}\)-module -- is not one-to-one. Nevertheless, this relationship is well understood. Namely, Fernando himself established\dots -% TODO: Define the conjugation of a p-mod by an element of the Weil group +% TODOO: Define the conjugation of a p-mod by an element of the Weil group % beforehand \begin{proposition}[Fernando] Given a parabolic subalgebra \(\mathfrak{p} \subset \mathfrak{g}\), there @@ -343,7 +345,8 @@ characterizations of cuspidal modules. \end{example} %% TODOO: Do we need this proposition? I think this only comes up in the -%% classification of simple completely reducible coherent families +%% classification of simple completely reducible coherent families. This could +%% stated in the end when we discuss the classification %\begin{proposition} % If \(\mathfrak{g} = \mathfrak{z} \oplus \mathfrak{s}_1 \oplus \cdots \oplus % \mathfrak{s}_n\), where \(\mathfrak{z}\) is the center of \(\mathfrak{g}\) @@ -373,7 +376,8 @@ a cuspidal representations we have encoutered so far: the \(\mathfrak{sl}_2(K)\)-module \(K[x, x^{-1}]\) of Laurent polynomials -- i.e. example~\ref{ex:laurent-polynomial-mod}. -% TODO: Add a definition of the ring of differential operators somewhere? +% TODO: Add a reference to Coutinho or something on the definition of the ring +% of differential operators of a given algebra Our first observation is that \(\mathfrak{sl}_2(K)\) acts in \(K[x, x^{-1}]\) via differential operators. In other words, the action map \(\mathcal{U}(\mathfrak{sl}_2(K)) \to \operatorname{End}(K[x, x^{-1}])\) @@ -422,7 +426,7 @@ where the maps \(\mathcal{U}(\mathfrak{sl}_2(K)) \to \operatorname{Diff}(K[x, x^{-1}])\) and \(\operatorname{Diff}(K[x, x^{1}]) \to \operatorname{End}(K[x, x^{-1}])\) are the ones from the previous diagram. -% TODO: Point out that the twisting automorphism does not fact to an +% TODOO: Point out that the twisting automorphism does not fact to an % automorphism of the universal enveloping algebra of sl2, but it factor % trought an automorphism of the localization of this algebra by f @@ -575,7 +579,7 @@ to a completely reducible coherent extension of \(V\). \(\mathcal{M}[\lambda]\) has finite length as a \(\mathfrak{g}\)-module. \end{lemma} -% TODO: Point out this construction is NOT functorial, since it depends on the +% TODOO: Point out this construction is NOT functorial, since it depends on the % choice of composition series \begin{corollary} Let \(\mathcal{M}\) be a coherent family of degree \(d\). There exists a @@ -1267,8 +1271,8 @@ It should now be obvious\dots There exists a coherent extension \(\mathcal{M}\) of \(V\). \end{proposition} -% TODO: Point out that here we have to fix representatives, so this -% construction is, once again, not functorial +% TODOO: Point out that here we have to fix representatives of the cosets, so +% this construction is, once again, not functorial \begin{proof} Take \[ @@ -1359,7 +1363,6 @@ Lo and behold\dots \(\operatorname{Ext}(V)\) is unique. \end{proof} -% TODO: Remove this % This is a very important theorem, but since we won't classify the coherent % extensions in here we don't need it, and there is no other motivation behind % it. Including this would also require me to explain what central characters