| ordered≤(a0 ' + y0), x1 ⊑ a0 ' + y0, (∃ x0. x1 ⊑ x0 ∧ ordered≤(x0)) → ordered≤(x1) ⊦ x1 = [], a0 < a, ¬ x1.first < a ∧ ordered≤(x1) |
x1 = a1 + y, ordered≤(a0 ' + y0), x1 ⊑ a0 ' + y0, (∃ x0. x1 ⊑ x0 ∧ ordered≤(x0)) → ordered≤(x1) ⊦ x1 = [], a0 < a, ¬ a1 < a ∧ ordered≤(x1)
Used simplifier rules: x ≠ [] ⊦ a = x.first ∧ y = x.rest ↔ x = a + y; (elim) Used terms: x1, a1, y