| ⊦ ¬ i ≤ 0 ∧ ¬ 0 ≤ j, ¬ 0 ≤ i ∧ ¬ j ≤ 0, i * j = 1 ↔ abs(j) = 1 ∧ i = j, ¬ i ≤ 0 ∧ 1 < j |
i ≤ 0 ⊦ ¬ i ≤ 0 ∧ ¬ 0 ≤ j, ¬ 0 ≤ i ∧ ¬ j ≤ 0, i * j = 1 ↔ abs(j) = 1 ∧ i = j, ¬ i ≤ 0 ∧ 1 < j
⊦ i ≤ 0, ¬ i ≤ 0 ∧ ¬ 0 ≤ j, ¬ 0 ≤ i ∧ ¬ j ≤ 0, i * j = 1 ↔ abs(j) = 1 ∧ i = j, ¬ i ≤ 0 ∧ 1 < j
Used formulas: i ≤ 0