| i * i0 = 1 + ~ j0 * j, 1 = i * i0 + j * j0, gcd(i, j) = 1, 0 ≤ j, 0 ≤ i ⊦ 0 ≤ i0 ∧ j | i * i0 - 1, ∃ i0. 0 ≤ i0 ∧ j | i * i0 - 1 |
i * i0 = 1 + ~ j0 * j, 1 = (1 + ~ j0 * j) + j * j0, gcd(i, j) = 1, 0 ≤ j, 0 ≤ i ⊦ 0 ≤ i0 ∧ j | 1 + ~ j0 * j - 1, ∃ i0. 0 ≤ i0 ∧ j | i * i0 - 1