1 < i, 0 < i ⊦ int2bits(i) = int2bits(i / 2) + (i % 2 = 1)'
Used simplifier rules: ⊦ i < j ∧ 0 < i → 0 < j ∧ 1 < j; (forward)% ⊦ i < j ∧ 0 ≤ i → 0 < j; (forward)