0 ≤ s2i(i2s(i)), i < 0, ~65536 ≤ i, i < ~32768 ⊦ s2i(i2s(i)) = i + 65536
Used simplifier rules: ⊦ i < j ∧ ¬ i0 < j → ¬ i0 < i;% ⊦ ¬ i ≤ j ↔ j < i;