⊦ m ≤ n ↔ (∃ n0. m + n0 = n)
n1 < n0, m < m1 * n, m1 * n0 + n1 < m1 * n, m1 * n0 + n1 ≤ m, ∃ n1. n + n1 = n0 ⊦ m1 = 0, n = 0
Used terms: n0, n