| j < 0 ⊦ j = 0, i1 = 0, rational(i1 * i, ~ i1 * ~ j) = rational(i, j) |
i1 * i = ~ i1 * ~ i, j < 0 ⊦ j = 0, i1 = 0, rational(i1 * i, ~ i1 * ~ j) = rational(i, j)
Used simplifier rules: ⊦ ~ i * j = ~(i * j);% ⊦ i * j * j0 = (i * j) * j0;% ⊦ i * j = j * i;% ⊦ ~ ~ i = i;% ⊦ i ≠ 0 → (i * j = i * j0 ↔ j = j0); Used formulas: i1 * i = ~ i1 * ~ i