# s1 ≤ n, # s0 ≤ m, m + n + 1 < #(s0 ∪ s1) ⊦
Used simplifier rules: f: ⊦ m < n → n ≠ 0; from specification nat-basic1%f: ⊦ m < n → n ≠ 0; (forward) from specification nat-basic1