| ⊦ n < # x ∧ list2set(x) ∩ s = ∅ ∧ list2set(x) ∩ s0 = ∅ → list2set(firstn(n, x)) ∩ (s ∪ s0) = ∅ |
list2set(x) ∩ s0 = ∅, list2set(x) ∩ s = ∅, n < # x ⊦ #(list2set(firstn(n, x)) ∩ (s ∪ s0)) = 0, list2set(firstn(n, x)) ∩ (s ∪ s0) = ∅, x = []
Used simplifier rules: ⊦ # s ≠ 0 → s ≠ ∅; (forward)% ⊦ # x = 0 ↔ x = [];% ⊦ s ≠ ∅ → # s ≠ 0; (forward)% ⊦ m < n → n ≠ 0; (forward)