| ∀ ns0, n, m. # ns0 < # ns → true → (n ∈ below(ns0, m) ↔ n ∈ ns0 ∧ n < m) ⊦ n ∈ below(ns, m) ↔ n ∈ ns ∧ n < m |
∀ ns0, n, m. # ns0 < # ns → true → (n ∈ below(ns0, m) ↔ n ∈ ns0 ∧ n < m) ⊦ n ∈ below(ns, m) ↔ n ∈ ns ∧ n < m, ns = ∅
Used simplifier rules: below-base: ⊦ below(∅, m) = ∅;% ⊦ ¬ n ∈ ∅; (s) Used formulas: ns = ∅