Hello everyone

I hope you can help me out with the following case.

I’m trying to write the set of equations (20) and (21) as shown in the attached file, but I’m having a hard time understanding how to write them given the conditions “when(x(i,j,m)=0 and x(i,j,m)=1)”.

So far, I wrote 20 as:

r20(m)…sum((i,j),t(i,j)*x(i,j,m))+sum((i,N(j)), h(j)*x(i,j,m))+sum((i,F(j)),((Cm-y(i,j,m))/r)) =l=Hs;

and 21 as two equations:

r21a(F,m)…(Cm-y(i,F,m))/r =g=0; Here set i is not controlled.

r21b(F,m)…(Cm-y(i,j,m))/r =l=H*sum(i,x(i,j,m)); Here It is controlled in the sum but not for the y(i,j,m) variable.

The model is from this article:

https://ac.els-cdn.com/S2352146516000089/1-s2.0-S2352146516000089-main.pdf?_tid=60bf7f42-ae1b-42a2-b16b-9a08fdbac586&acdnat=1543109774_132d486a9be301e65541f677a490775b

I appreciate your help.