Does anyone know of a way that mathematica can solve the summation below. I understand you cannot use capital letter when defining variable, but this is just to demonstrate the basic idea I am getting at. I am trying to see what I can do and get away with in mathematica, so the variables may seem trivial.
These would be the defined sets
Subscript[X, 1, 1] = 1
Subscript[X, 1, 2] = 2
Subscript[X, 2, 1] = 3
Subscript[X, 1, 2] = 4
A[j] = {1, 2}
J = {1, 2}
