I want to write this expression but I know that is no possible because I sum j and for all j. I think It would have 2 indexes like j ,j´ but I don’t know how to do it gams.

Please, Can you help me with this? I find something with alias but I dont know how to use.

**GAMS:**

alias(j,jb)

eq(j) .. (sum(p,is(j,p))+ sum(i,(th(j,i)*Y(i,j))) - sum(k,dm(j,k))) =G= sum(jb,(sum(p,is(jb,p))+ sum(i,(th(jb,i)*Y(i,j))) - sum(k,dm(jb,k)))))*V_NEG*(dm(j,k)/(sum(jb,dm(jb,k))));

**EQUATION:**