Hi
i am trying to do modelling in gams but i faced such a problem:

in one of my equations i write

precedence(i)… sum(k, x(i,k)*k) =L= something for example.

When i write like this it gives dimension different error. But if i write this equation in opened form for i=1 for example, it doesnt give any error. But i need to write this in closed form.
By the way, the error happens only if i multiply k with x (k*x(i,k))

Related information:
k is a set /15/
i is a set /15/
x(i,k) is a binary variable