⊦ 0 < i → n→i(i→n(i)) = i
Used simplifier rules: abs-neg: ⊦ i→n(~ i) = i→n(i);% ⊦ 0 < ~ i ↔ i < 0; (s)% ⊦ ~ i = j ↔ i + j = 0; (s) Used terms: ~ i