thanks Alec, i'll try.

hi, thank you for your answers in fact i need to use it on some sort of "two sided complementary geometric" matrix sums: A^0.P.Q^k + A^1.P.Q^(k-1) + A^2.P.Q^(k-2)+ ... + A^(k-1).P.Q + A^k.P.Q^0 it woluld be desirable that the new operator was treated as matrix product, is it possible?