I will appriciate any help to the following statement for gams:

Vg(t,i) =g=0;

Vd(t,i) =l=0;

## If Vg(t,i) >0 then Vd(t,i) =0 else Vd(t,i)<0

and

If Vd(t,i)<0 then Vg(t,i)=0 else Vg(t,i)>0

Thanks in advanced.