gcd(m, n) = 0, n < m ⊦ m = n, m = 0
Used simplifier rules: f: ⊦ m < n → n ≠ 0; (forward) from specification nat-basic1%neq-01: ⊦ m ≠ n → (¬ m < n ↔ n < m); from specification nat-basic1