1 = i * i0 + j0 * j, gcd(i, j) = 1, i0 < 0, 0 < i, 0 ≤ j ⊦ i = 0, ∃ i0. 0 ≤ i0 ∧ j | i * i0 - 1
Used simplifier rules: ⊦ i < j ↔ ¬ j ≤ i; (ss)