| j0 < 0, i0 < 0, j0 < j, j < 0, i < 0, j0 + 1 < 0, i0 * j0 ≤ i * j, i0 ≤ i ⊦ |
j0 + 1 < 0, i < 0, j < 0, j0 < j, i0 < 0, j0 < 0, i * j < i * j0, i0 ≤ i, i0 * j0 ≤ i * j ⊦
Used simplifier rules: ls-neg: ⊦ i < 0 → (i * j < i * j0 ↔ j0 < j);%associativity: ⊦ i * j * j0 = (i * j) * j0;%commutativity: ⊦ i * j = j * i;% ⊦ i < j ↔ ¬ j ≤ i; (ss)% ⊦ i < j → (j ≤ i ↔ false); (as) Used formulas: i * j < i * j0