- Commit
- c4e6ca092607a5b3f14351934351f10d1aec3ea8
- Parent
- f21bd3529537b0333f19ed79e176a05e7b292d55
- Author
- Pablo <pablo-escobar@riseup.net>
- Date
Ajustados comentários iniciais sobre a prova do teorema do peso integral dominante
Source code for my notes on representations of semisimple Lie algebras and Olivier Mathieu's classification of simple weight modules
Ajustados comentários iniciais sobre a prova do teorema do peso integral dominante
1 file changed, 21 insertions, 22 deletions
Status | File Name | N° Changes | Insertions | Deletions |
Modified | sections/semisimple-algebras.tex | 43 | 21 | 22 |
diff --git a/sections/semisimple-algebras.tex b/sections/semisimple-algebras.tex @@ -2121,33 +2121,32 @@ Now the only thing we are missing for a complete classification is an existence and uniqueness theorem analogous to theorem~\ref{thm:sl2-exist-unique} and theorem~\ref{thm:sl3-existence-uniqueness}. Lo and behold\dots +\begin{definition} + An element \(\lambda\) of \(P\) such that \(\lambda(H_\alpha) \ge 0\) for all + \(\alpha \in \Delta^+\) is referred to as an \emph{integral dominant weight + of \(\mathfrak{g}\)}. +\end{definition} + \begin{theorem}\label{thm:dominant-weight-theo} - For each \(\lambda \in P\) such that \(\lambda(H_\alpha) \ge 0\) for - all positive roots \(\alpha\) there exists precisely one irreducible - representation \(V\) of \(\mathfrak{g}\) whose highest weight is \(\lambda\). + For each dominant integeral \(\lambda \in P\) there exists precisely one + irreducible finite-dimensional representation \(V\) of \(\mathfrak{g}\) whose + highest weight is \(\lambda\). \end{theorem} -\begin{note} - An element \(\lambda\) of \(P\) such that \(\lambda(H_\alpha) \ge 0\) for all - \(\alpha \in \Delta^+\) is usually referred to as an \emph{integral - dominant weight of \(\mathfrak{g}\)}. -\end{note} - -Unsurprisingly, our strategy is to copy what we did in the previous section. -The ``uniqueness'' part of the theorem follows at once from the argument used -for \(\mathfrak{sl}_3(K)\), and the proof of existence of can once again be -reduced to the proof of\dots +Fix some dominant integral \(\lambda \in P\). The ``uniqueness'' part of the +theorem follows at once from the argument used for \(\mathfrak{sl}_3(K)\). -\begin{theorem}\label{thm:weak-dominant-weight} - There exists \emph{some} -- not necessarily irreducible -- finite-dimensional - representation of \(\mathfrak{g}\) whose highest weight is \(\lambda\). -\end{theorem} +\begin{proposition} + Let \(V\) and \(W\) be irreducible finite-dimensional + \(\mathfrak{g}\)-modules whose highest weight is \(\lambda\). Then \(V \cong + W\). +\end{proposition} -The trouble comes when we try to generalize the proof of -theorem~\ref{thm:weak-dominant-weight} we used for the case when \(\mathfrak{g} -= \mathfrak{sl}_3(K)\). The issue is that our proof relied heavily on our -knowledge of the roots of \(\mathfrak{sl}_3(K)\). Instead, we need a new -strategy for the general setting. +The ``existance'' part is more nuanced. Our first instinct is, of course, to +try to generalize the proof used for \(\mathfrak{sl}_3(K)\). The issue is that +our proof relied heavily on our knowledge of the roots of +\(\mathfrak{sl}_3(K)\). Instead, we need a new strategy for the general +setting. % TODOO: Add further details. Turn this into a proper proof? Alternatively, one could construct a potentially infinite-dimensional