| ordered≤(x0), ∀ a1. ordered≤(x0 -1l a1) ⊦ a = a0, x0 = [], x0.head < a0, ordered≤(a0 ' + (x0 -1l a)) |
x0 = a2 + y, ordered≤(x0), ∀ a1. ordered≤(x0 -1l a1) ⊦ a = a0, x0 = [], a2 < a0, ordered≤(a0 ' + (x0 -1l a))
Used simplifier rules: x ≠ [] ⊦ a = x.head ∧ y = x.tail ↔ x = a + y; (elim) Used terms: x0, a2, y