⊦ st1 = st2 ↔ (∀ a. (a ∈ st1 ↔ a ∈ st2) ∧ st1[a] = st2[a])
dom st ∩ s = ∅ ⊦ ∀ a. (a ∈ st \ s ↔ a ∈ st) ∧ (st \ s)[a] = st[a]
Used terms: st, st \ s