Cartan datum

Cartan datum \((A,P^{\vee},P,\Pi^{\vee},\Pi)\)

• \(A=(a_{ij})_{i,j\in I}\) GCM
• \(P^{\vee}=(\bigoplus_{i\in I}\mathbb{Z}h_{i})\bigoplus(\bigoplus_{j=1}^{\operatorname{corank}(A)}\mathbb{Z}d_{j})\) : co-weight lattice
• \(\mathfrak{h}=\mathbb{Q}\otimes_{\mathbb{Z}} P^{\vee}\) : Cartan subalgebra
• \(P=\{\lambda\in\mathfrak{h}^{*}|\lambda(P^{\vee})\subset \mathbb{Z}\}\) : weight lattice
• \(\Pi^{\vee}=\{h_{i}|i\in I\}\) : simple coroots
• \(\Pi=\{\alpha_{i}\in\mathfrak{h}^{*}|i\in I, \alpha_{i}(h_j)=a_{ji}\}\) : simple roots

fundamental weights

\(\{\Lambda_{i}\in\mathfrak{h}^{*}|i\in I, \Lambda_{i}(h_j)=\delta_{ij},\Lambda_{i}(d_j)=0\}\)

\(Q=\bigoplus_{i\in I}\mathbb{Z}\alpha_{i}\) : root lattice

Weyl group \(W=\langle r_{i}|i\in I\rangle\)

세르 관계식

• l : 리대수 \(\mathfrak{g}\)의 rank
• \((a_{ij})\) : 카르탄 행렬
• 생성원 \(e_i,h_i,f_i , (i=1,2,\cdots, l)\)
• 세르 관계식
  • \(\left[h_i,h_j\right]=0\)
  • \(\left[e_i,f_j\right]=\delta _{i,j}h_i\)
  • \(\left[h_i,e_j\right]=a_{i,j}e_j\)
  • \(\left[h_i,f_j\right]=-a_{i,j}f_j\)
  • \(\left(\text{ad} e_i\right){}^{1-a_{i,j}}\left(e_j\right)=0\) (\(i\neq j\))
  • \(\left(\text{ad} f_i\right){}^{1-a_{i,j}}\left(f_j\right)=0\) (\(i\neq j\))