| i = i0 / gcd(i0, j0) * gcd(i, j), j = j0 / gcd(i0, j0) * gcd(i, j), 0 < j, 0 < j0 ⊦ j = 0, i0 / gcd(i0, j0) * gcd(i, j) * j0 = i0 * j0 / gcd(i0, j0) * gcd(i, j), j0 = 0, i0 = 0, i = 0 |
⊦ i * j = j * i
i = i0 / gcd(i0, j0) * gcd(i, j), j = j0 / gcd(i0, j0) * gcd(i, j), 0 < j, 0 < j0 ⊦ j = 0, i0 / gcd(i0, j0) * j0 * gcd(i, j) = i0 * j0 / gcd(i0, j0) * gcd(i, j), j0 = 0, i0 = 0, i = 0
Used terms: j0, gcd(i, j)