| ordered≤(a ' + x1), ordered≤(x1 + a0 ' + y), ∀ x. ordered≤(x) ∧ (x ≠ [] → ¬ x.head < x1.last) → ordered≤(x1 + x) ⊦ x1 = [], a0 < x1.last, ordered≤(a ' + x1 + a0 ' + y) |
⊦ ordered≤(y) ↔ # y ≤ 1 ∨ ¬ y.tail.head < y.head ∧ ordered≤(y.tail)
ordered≤(x1 + a0 ' + y), ordered≤(a ' + x1), ∀ x. ordered≤(x) ∧ (x ≠ [] → ¬ x.head < x1.last) → ordered≤(x1 + x) ⊦ x1 = [], a0 < x1.last, #(a ' + x1 + a0 ' + y) ≤ 1, ¬ (a ' + x1 + a0 ' + y).tail.head < (a ' + x1 + a0 ' + y).head ∧ ordered≤((a ' + x1 + a0 ' + y).tail)
Used terms: a ' + x1 + a0 ' + y