| j0 < j, 0 < j, 0 ≤ j0, 0 ≤ i0 ⊦ j = 0, i0 = (i0 * j + j0 < (1 + 2 * i0 / 2) * j ⊃ 0;1) + 2 * i0 / 2 |
i0 * j + j0 < (1 + 2 * i0 / 2) * j, j0 < j, 0 < j, 0 ≤ j0, 0 ≤ i0 ⊦ i0 = 0 + 2 * i0 / 2, j = 0
¬ i0 * j + j0 < (1 + 2 * i0 / 2) * j, j0 < j, 0 < j, 0 ≤ j0, 0 ≤ i0 ⊦ i0 = 1 + 2 * i0 / 2, j = 0