δ ( E i , i + k ) = E i , i + k ∧ ( E i , i − E i + k , i + k ) + 2 ∑ j = 1 k − 1 E i + j , i + k ∧ E i , i + j {\displaystyle \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}}
δ ( E i + k , i ) = E i + k , i ∧ ( E i , i − E i + k , i + k ) + 2 ∑ j = 1 k − 1 E i + k , i + j ∧ E i + j , i {\displaystyle \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}}
δ ( E i , i ) = 0 {\displaystyle \delta (E_{i,i})=0}
