| i + j = (i1 * i + j0) + 1, j0 < i, i * i0 < j, 0 < i, 0 < i + j, 0 ≤ j, i1 ≤ i0, 0 ≤ j0 ⊦ |
i + j = (i1 * i + j0) + 1, j = (i1 - 1) * i + j0 + 1, 0 < i + j, 0 < i, i * i0 < j, j0 < i, 0 ≤ j0, i1 ≤ i0, 0 ≤ j ⊦
i + j = (i1 * i + j0) + 1, 0 < i + j, 0 < i, i * i0 < j, j0 < i, 0 ≤ j0, i1 ≤ i0, 0 ≤ j ⊦ j = (i1 - 1) * i + j0 + 1
Used formulas: j = (i1 - 1) * i + j0 + 1