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