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
Used terms: i0