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