a:=matrix ([[1,2],[0,9]]?) inverse(a) )expose TriangularMatrixOperations? UpTriBddDenomInv?(a,9) UpTriBddDenomInv?(a,7) a:=transpose(a) inverse(a) LowTriBddDenomInv?(a,9) LowTriBddDenomInv?(a,7)