| m + n ≤ m0 + n ⊦ m0 + n - m + n = dist(m, m0) |
m ≤ m0 ⊦ m0 - m = dist(m, m0)
Used simplifier rules: ⊦ m + n ≤ m + n0 ↔ n ≤ n0; (s)%c: ⊦ m + n = n + m; from specification nat-basic%a: ⊦ (m + n0) + n1 = m + n0 + n1; from specification nat-basic% ⊦ m + n - n + n1 = m - n1; (s)