| m0 < m, m0 + n < m + n ⊦ m + n - m0 + n = dist(m, m0) |
m0 < m ⊦ m - m0 = 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)