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