| union(asar, n, m0) ⊆ as ↔ (∀ n0. n ≤ n0 ∧ n0 < n + m0 → asar[n0] ⊆ as), ∀ n0. n ≤ n0 ∧ ¬ n + m0 < n0 → asar[n0] ⊆ as ⊦ asar[n + m0] ∪ union(asar, n, m0) ⊆ as |
⊦ as ∪ as0 ⊆ as1 ↔ as ⊆ as1 ∧ as0 ⊆ as1
union(asar, n, m0) ⊆ as ↔ (∀ n0. n ≤ n0 ∧ n0 < n + m0 → asar[n0] ⊆ as), ∀ n0. n ≤ n0 ∧ ¬ n + m0 < n0 → asar[n0] ⊆ as ⊦ asar[n + m0] ⊆ as ∧ union(asar, n, m0) ⊆ as
Used terms: as, union(asar, n, m0), asar[n + m0]