⊦ st1 = st2 ↔ (∀ a. (a ∈ st1 ↔ a ∈ st2) ∧ st1[a] = st2[a])
a ∈ s ⊦ s = ∅, ∀ a0. (a0 ∈ st[a, d] \ s ↔ a0 ∈ st \ s) ∧ (st[a, d] \ s)[a0] = (st \ s)[a0], # s = 0
Used terms: st \ s, st[a, d] \ s