j1 = i0 +1, 0 < i, ∀ i, j0. 0 < i → (i * j1 < i * j0 ↔ j1 < j0) ⊦ i * i0 < i * j0 ↔ i0 < j0
Used simplifier rules: ⊦ i = j -1 ↔ j = i +1; (elim) Used terms: j1, i0