ApCoCoA-1:BBSGen.JacobiLin
BBSGen.JacobiLin
This function computes the K[c]-linear polynomial entries of the Jacobi identity matrix [ A_m[A_k,A_l ] ]+[ A_k[ A_l,A_m]] +[ A_l[A_m,A_k ] ] where m,k,l is from {1...n}.
Syntax
BBSGen.JacobiLin(OO,BO,N); BBSGen.JacobiLin(OO:LIST,BO:LIST,N:INTEGER):MATRIX
Description
Let R:=K[x_1,...,x_N] and A_k be the generic multiplication matrix associated to x_k. Let tau^kl_ij be the polynomial in the (i,j) position of the [A_k,A_l] where k,l in {1,..,N}.
Let m,k,l in {1,...,N}. This function computes the polynomial entries of the Jacobi identity J^mkl= [ A_m[A_k,A_l ] ]+[ A_k[ A_l,A_m]] +[ A_l[A_m,A_k]] that has constant coeffiecients. During the computation entries of the commutators Tau^kl_ij will be considered as indeterminates t[k,l,i,j] in K[c[1..Mu,1..Nu],t[1..N,1..N,1..Mu,1..Mu]]. Therefore the result of BBSGen.JacobiLin is a list of polynomials from the ring K[t[1..N,1..N,1..Mu,1..Mu]].
Please note that this function does not work for the case, where N=2.
@param Order ideal OO, border BO, the number of indeterminates of the polynomial ring K[x_1,...,x_N].
@return The K[c]-linear entries of the Jacobi Identity J^ikl. .
Example
Use R::=QQ[x[1..3]];
OO:=[1,x[1]];
BO:=$apcocoa/borderbasis.Border(OO);
Mu:=Len(OO);
Nu:=Len(BO);
N:=Len(Indets());
Use XX::=QQ[c[1..Mu,1..Nu],t[1..N,1..N,1..Mu,1..Mu]];
BBSGen.JacobiLin(OO,BO,N);
[[ [ -t[2,3,1,2],0],
[ t[2,3,1,1] - t[2,3,2,2], t[2,3,1,2]]]]
