⊦ i < j ↔ i +1 = j ∨ i +1 < j
i0 +1 = j + 1 ∨ i0 +1 < j + 1, ∀ j. i0 < j → (∃ i1. j = i0 + i1 ∧ 0 < i1) ⊦ ∃ i. j + 1 = i0 + i ∧ 0 < i
Used terms: j + 1, i0