> i am trying to write a constraint with Gurobi, but i dont know how to write? please help me.
>
> Xij <= Zkl for all i belongs to I:S(i)=k and j belongs to B:R(j)=l
If you want to use algebraic and set notation, you should try a modeling language such as AMPL. Otherwise, you need to use data structures from a traditional programming language like Java or Python.