i ^ j ≤ i ^ j0 ↔ j ≤ j0, i ^ j < i ^ j0, 0 < i, 1 < i, 0 ≤ j, j0 ≤ j ⊦
Used simplifier rules: ⊦ i ≤ 0 ∧ 0 ≤ j → i ≤ j; (s)