| (i + j) / 2 < i, i ≤ j, (i + j) / 2 < j ⊦ |
⊦ 0 < j ∧ 0 ≤ i → (i0 = i / j ∧ j0 = i % j ↔ i = i0 * j + j0 ∧ 0 ≤ j0 ∧ j0 < j ∧ 0 ≤ i0)
(i + j) / 2 < i, i ≤ j, (i + j) / 2 < j ⊦ 0 < 2 ∧ 0 ≤ i + j
i + j = i0 * 2 + j0 ∧ 0 ≤ j0 ∧ j0 < 2 ∧ 0 ≤ i0 ∧ 0 < 2 ∧ 0 ≤ i + j, i0 < i, i ≤ j, i0 < j ⊦
Used terms: i + j, 2, i0, j0