0 ≤ i, 0 ≤ j ⊦ 2 ^ i / 2 ^ j = 2 ^ (i - j)
Used simplifier rules: ⊦ ~1 < i ↔ 0 ≤ i; (s)%numlef-01: ⊦ (* i) ≤ j → i - 1 < j; (forward) from specification int-abs