| ⊦ ins≤(a, x + a0 ') = ins≤(a, x) + a0 ', a0 < a |
∀ a, a0. ins≤(a, x0 + a0 ') = ins≤(a, x0) + a0 ' ∨ a0 < a ⊦ ins≤(a, (a1 + x0) + a0 ') = ins≤(a, a1 + x0) + a0 ', a0 < a
Used simplifier rules: ins-one-01: ⊦ ¬ b < a → ins≤(a, b ') = a ' + b ';%ins-e: ⊦ ins≤(a, []) = a ';%list freely generated by [], +;;%Nil: ⊦ [] + x = x; from specification list%a: ⊦ (x + y) + z = x + y + z; from specification list%app-08: ⊦ a ' + x = a ' + y ↔ x = y; from specification list