[GAP Forum] MatrixOfAction

[Jan Draisma]

Dear Gap-Forum,

I'm having the following problem with MatrixOfAction:

g:=SimpleLieAlgebra("A",1,Rationals);;
x:=GeneratorsOfAlgebra(g);;
V:=HighestWeightModule(g,[1]);;
W:=DirectSumOfAlgebraModules(V,V);;
B:=Basis(W);;
MatrixOfAction(B,x[1]);

Error, no method found! ...

Is this use of MatrixOfAction (or in Coefficients, where the problem
seems to be located) unsupported?

Best wishes,

  Jan