Hi, I am trying to do define a matrix of differential operators for e.g |diff((),x) , 0 | | 0 , diff((),y)| |diff((),y) , 0 | | 0 , diff((),x)| once this 4x2 operator is defined i can apply it to any function of two variables f(x,y) or a compatible(in size) matrix of such functions. How can I define such an operator in maple? Thanks, saurabh