| x ⊆m y + (y0 -1l a), a ∈ y0 ⊦ ∀ a0. #oc(a0, x) ≤ #oc(a0, (y + y0) -1l a) |
#oc(a0, (y + y0) -1l a) < #oc(a0, x), a ∈ y0, x ⊆m y + (y0 -1l a), a0 ∈ x ⊦
Used simplifier rules: oc-zero: ⊦ #oc(a, x) = 0 ↔ ¬ a ∈ x;%f: ⊦ m < n → n ≠ 0; (forward) from specification nat-basic1%lels-01: ⊦ ¬ m ≤ n ↔ n < m; from specification nat