Yes, sorry. I hope the following will clarify:
S is a finite set of elements ki
V is a subset of S, e.g. v4={k1,k3}
E is a finite ensemble of V, e.g. E = { v1={k1}, v2={k1,k2}, v4={k1,k3}, v4={k2,k4,k5} }
f(S, V) → ]-∞,∞], (ki,vj) → wij, with wij infinite only if ki ⊄ vj.
The problem is to...