I define:

set t

variable x(t).

I want to express this equation as a constraint in my model:

x(t=T)>=sum(t,x(t<=T-1))

which means the variable

*x*at time slot

*t*should be equal or larger than the sum of

*x*at all time slot before

*t*.

I tried a lot of ways to express it as an equation in Gams, but all of them doesn't work. Can someone here help me dealing with this? Thanks!

Lawrence