- Commit
- 124b15e99943534220663298138bb8b0ef3874c3
- Parent
- 7ec8aac792bf1da45a06d0b87f2834361ad2a967
- Author
- Pablo <pablo-escobar@riseup.net>
- Date
Revised the third chapter (again)
Implemented Kashuba's suggestions
Source code for my notes on representations of semisimple Lie algebras and Olivier Mathieu's classification of simple weight modules
Revised the third chapter (again)
Implemented Kashuba's suggestions
1 file changed, 12 insertions, 12 deletions
Status | File Name | N° Changes | Insertions | Deletions |
Modified | sections/sl2-sl3.tex | 24 | 12 | 12 |
diff --git a/sections/sl2-sl3.tex b/sections/sl2-sl3.tex @@ -289,13 +289,13 @@ clues on why \(h\) was a sure bet and the race was fixed all along. \section{Representations of \(\mathfrak{sl}_3(K)\)}\label{sec:sl3-reps} The study of representations of \(\mathfrak{sl}_2(K)\) reminds me of the -difference the derivative of a function \(\RR \to \RR\) and that of a smooth -map between manifolds: it's a simpler case of something greater, but in some -sense it's too simple of a case, and the intuition we acquire from it can be a -bit misleading in regards to the general setting. For instance, I distinctly -remember my Calculus I teacher telling the class ``the derivative of the -composition of two functions is not the composition of their derivatives'' -- -which is, of course, the \emph{correct} formulation of the chain rule in the +difference between the derivative of a function \(\RR \to \RR\) and that of a +smooth map between manifolds: it's a simpler case of something greater, but in +some sense it's too simple of a case, and the intuition we acquire from it can +be a bit misleading in regards to the general setting. For instance, I +distinctly remember my Calculus I teacher telling the class ``the derivative of +the composition of two functions is not the composition of their derivatives'' +-- which is, of course, the \emph{correct} formulation of the chain rule in the context of smooth manifolds. The same applies to \(\mathfrak{sl}_2(K)\). It's a simple and beautiful @@ -367,8 +367,8 @@ In our analysis of \(\mathfrak{sl}_2(K)\) we saw that the eigenvalues of \(h\) differed from one another by multiples of \(2\). A possible way to interpret this is to say \emph{the eigenvalues of \(h\) differ from one another by integral linear combinations of the eigenvalues of the adjoint action of -\(h\)}. In English, the eigenvalues of of the adjoint actions of \(h\) are -\(0\) and \(\pm 2\) since +\(h\)}. In English, the eigenvalues of the adjoint actions of \(h\) are \(0\) +and \(\pm 2\) since \begin{align*} \operatorname{ad}(h) e & = 2 e & \operatorname{ad}(h) f & = -2 f & @@ -693,9 +693,9 @@ all weights lie in the rational span of \(\{\alpha_1, \alpha_2, \alpha_3\}\), we may as well draw them in the Cartesian plane. To proceed we once more refer to the previously established framework: next we -saw that the eigenvalues of \(h\) formed an unbroken string of integers -symmetric around \(0\). To prove this we analyzed the right-most eigenvalue of -\(h\) and its eigenvector, providing an explicit description of the irreducible +saw that the eigenvalues of \(h\) form an unbroken string of integers symmetric +around \(0\). To prove this we analyzed the right-most eigenvalue of \(h\) and +its eigenvector, providing an explicit description of the irreducible representation of \(\mathfrak{sl}_2(K)\) in terms of this vector. We may reproduce these steps in the context of \(\mathfrak{sl}_3(K)\) by fixing a direction in the plane an considering the weight lying the furthest in that