| m0 + n < m + n, m0 < m ⊦ m + n - m0 + n = dist(m, m0), m = 0 |
m0 < m ⊦ m = 0, m - m0 = dist(m, m0)
Used simplifier rules: l: ⊦ m + n < m + n0 ↔ n < n0; from specification nat-basic2%c: ⊦ m + n = n + m; from specification nat-basic2%a: ⊦ (m + n0) + n1 = m + n0 + n1; from specification nat-basic2%cancel-01: ⊦ m + n - n + n1 = m - n1; from specification nat