- Commit
- 9ff3996bdda5ee739a3acda623b7a7757a574f7c
- Parent
- 07b9d2a5098e07ed07ef162527ea480f539545d2
- Author
- Pablo <pablo-escobar@riseup.net>
- Date
Pequena quebra em um parágrafo mais longo
Source code for my notes on representations of semisimple Lie algebras and Olivier Mathieu's classification of simple weight modules
Pequena quebra em um parágrafo mais longo
1 file changed, 9 insertions, 9 deletions
Status | File Name | N° Changes | Insertions | Deletions |
Modified | sections/semisimple-algebras.tex | 18 | 9 | 9 |
diff --git a/sections/semisimple-algebras.tex b/sections/semisimple-algebras.tex @@ -430,7 +430,7 @@ we introduce a distinguished element of \(\mathcal{U}(\mathfrak{g})\), known as all representations \(V\) of \(\mathfrak{g}\): its action commutes with the action of any other element of \(\mathfrak{g}\). - % TODOOO: Prove that the action is not zero when V is non-trivial + % TODOO: Prove that the action is not zero when V is non-trivial In particular, it follows from Schur's lemma that if \(V\) is finite-dimensional and irreducible then \(C\) acts in \(V\) as a scalar operator. @@ -1799,14 +1799,14 @@ simple calculation also shows that if \(i \ne j\) then the coefficient of in \(X\), for all \(X \in \mathfrak{gl}_n(K)\). In particular, if \([E_{i i}, X]\) is diagonal for all \(i\), then so is \(X\) -- i.e. \(\mathfrak{h}\) is self-normalizing. Hence \(\mathfrak{h}\) is a Cartan subalgebra of -\(\mathfrak{gl}_n(K)\). The intersection of such subalgebra with -\(\mathfrak{sl}_n(K)\) -- i.e. the subalgebra of traceless diagonal matrices -- -is a Cartan subalgebra of \(\mathfrak{sl}_n(K)\). In particular, if \(n = 2\) -or \(n = 3\) we get to the subalgebras described the previous two sections. - -The remaining question then is: if \(\mathfrak{h} \subset \mathfrak{g}\) is a -Cartan subalgebra and \(V\) is a representation of \(\mathfrak{g}\), does the -eigenspace decomposition +\(\mathfrak{gl}_n(K)\). + +The intersection of such subalgebra with \(\mathfrak{sl}_n(K)\) -- i.e. the +subalgebra of traceless diagonal matrices -- is a Cartan subalgebra of +\(\mathfrak{sl}_n(K)\). In particular, if \(n = 2\) or \(n = 3\) we get to the +subalgebras described the previous two sections. The remaining question then +is: if \(\mathfrak{h} \subset \mathfrak{g}\) is a Cartan subalgebra and \(V\) +is a representation of \(\mathfrak{g}\), does the eigenspace decomposition \[ V = \bigoplus_{\lambda \in \mathfrak{h}^*} V_\lambda \]