| i < 0 ⊦ abs(i) < i0, i0 < 0, gcd(abs(i), abs(i) - abs(i0)) = gcd(abs(i) - abs(i0), abs(i0)), 0 < i ∧ i < i0 + i |
⊦ gcd(i, j) = gcd(j, i)
i < 0 ⊦ abs(i) < i0, i0 < 0, gcd(abs(i) - abs(i0), abs(i)) = gcd(abs(i) - abs(i0), abs(i0)), 0 < i ∧ i < i0 + i
Used terms: abs(i) - abs(i0), abs(i)