⊦ inv(st) ↔ (∀ n. n ∈ st → inv(st[n]))
@(m, m0, 0) ∈ st, @(m, m0, 0) ∈ as, as ⊆ dom nodes(st), ∀ n. n ∈ st → inv(st[n]) ⊦ # as = 0, as = ∅
Used terms: st