0 ≤ i ⊦ i→n(i) = (* m) ↔ i = n→i(m)
¬ 0 ≤ 2 * i, i→n(2 * i) = m0 * 2 + n0, n0 < 2 ⊦ m0 = i→n(i)
0 ≤ 2 * i, 2 * i = n→i(m0 * 2 + n0), n0 < 2 ⊦ m0 = i→n(i)
Used terms: m0 * 2 + n0, 2 * i