Excuse me for this simple question, but kindly would like to know how to write the below mathematical expression (h belongs to H(l,p)) in GAMS (the one in red rectangular).

Here is my GAMS model, am I identifying it in the correct way? Please advise Kellogg Optimization Model.gms (3.83 KB)
Thanks in advance

But my question was how to write the expression Sum h ϵ H(l,p). For example, am I writing it correctly in the below code?
<C1(l,p,t)… sum(h$HLP(l,p),ALPHA(h,l,p,t)*MAKE(h,p,t)) =l= U(l,p,t) ;>