Notes for BBS/BCHKW-110516-160040.jpg

$\delta (E_{i,i+k})=E_{i,i+k}\wedge (E_{i,i}-E_{i+k,i+k})+2\sum _{j=1}^{k-1}E_{i+j,i+k}\wedge E_{i,i+j}$

$\delta (E_{i+k,i})=E_{i+k,i}\wedge (E_{i,i}-E_{i+k,i+k})+2\sum _{j=1}^{k-1}E_{i+k,i+j}\wedge E_{i+j,i}$

$\delta (E_{i,i})=0$