| j0 ≤ 0, abs(j0) < i, i * (i1 + 1) + j0 ≤ 0, 0 < i, j0 < i, i * (i1 + 1) + j0 < i ⊦ i * i0 < i * (i1 + 1) + j0 ↔ ¬ i1 < i0, i = i * (i1 + 1) + j0 |
i * i0 < i * (i1 + 1) + j0, j0 ≤ 0, abs(j0) < i, i * (i1 + 1) + j0 ≤ 0, 0 < i, j0 < i, i * (i1 + 1) + j0 < i ⊦ ¬ i1 < i0, i = i * (i1 + 1) + j0
¬ i1 < i0, j0 ≤ 0, abs(j0) < i, i * (i1 + 1) + j0 ≤ 0, 0 < i, j0 < i, i * (i1 + 1) + j0 < i ⊦ i * i0 < i * (i1 + 1) + j0, i = i * (i1 + 1) + j0