⊦ i | j ↔ (∃ i0. i * i0 = j)
gcd(i, j) = 1, ∃ i1. j * i1 = i * i0 - 1, 0 < j, 1 < j, 0 < i, 1 < i, 0 ≤ i0 ⊦ ∃ i0. (i * i0) % j = 1
Used terms: i * i0 - 1, j