⊦ ∃ i0, j0. gcd(i, j) = i * i0 + j * j0
gcd(i, j) = 1, ∃ i0, j0. gcd(i, j) = i * i0 + j * j0 ⊦ ∃ i0. j | i * i0 - 1
Used terms: i, j