| j < 0, j1 + j < 0, 0 ≤ j1, 0 ≤ i1 * j + j1 ⊦ i0 = i1 ∧ j0 = j1 ↔ i1 * j + j1 = i0 * j + j0 ∧ 0 ≤ j0 ∧ j0 + j < 0 ∧ i0 ≤ 0 |
i0 = i1, j0 = j1, j1 + j < 0, j < 0, 0 ≤ i1 * j + j1, 0 ≤ j1 ⊦ i1 * j + j1 = i0 * j + j0 ∧ 0 ≤ j0 ∧ j0 + j < 0 ∧ i0 ≤ 0
i1 * j + j1 = i0 * j + j0, j1 + j < 0, j < 0, j0 + j < 0, 0 ≤ i1 * j + j1, 0 ≤ j1, 0 ≤ j0, i0 ≤ 0 ⊦ i0 = i1 ∧ j0 = j1