⊦ 2^ m ≤ n ∧ n < 2^ m +1 → log2 n = m
¬(2^(log2 n + 1) ≤ 2 * n ∧ 2 * n < 2^ (log2 n + 1)+1) ⊦ log2(2 * n) = log2 n + 1, n = 0
Used terms: log2 n + 1, 2 * n