| gcd(i, j) = 1, i1 * abs(j) = i * i0 + 1, 0 < i0, i < 0, i < i0, i1 ≤ 0, i1 < i0, 1 < abs(j) ⊦ j = 0, j | i * i0 - 1, j | i0 * i + 1, ∃ i0. ≡mod(i * i0, 1, j) |
Used simplifier rules: div-abs: ⊦ i | abs(i) * j; from specification int-gcd%associativity: ⊦ i * j * j0 = (i * j) * j0; from specification int-mult%commutativity: ⊦ i * j = j * i; from specification int-mult