| #oc(a, y) + 1 < #oc(a, x), a ∈ x, y ⊆m x -1l a, ∀ a0. #oc(a0, x -1l a) ≤ #oc(a0, y) ⊦ |
Used simplifier rules: del1: ⊦ a ∈ x → #oc(a, x -1l a) = #oc(a, x) -1;%in-05: ⊦ a ∈ x → #oc(a, x) ≠ 0;% ⊦ n -1 = n - 1; (s)% ⊦ m ≤ n ↔ ¬ n < m; (ss)% ⊦ m < 1 ↔ m = 0; (s)%n0 ≤ n ⊦ n - n0 ≤ m ↔ n ≤ m + n0; (s)% ⊦ m < n → (n ≤ m ↔ false); (s) Used terms: a