rw [List.pairwise_cons] at ordered
case neg
α : Type
hl : LinearOrder α
inst✝ : DecidableRel LE.le
a x : α
xs : List α
ih : List.Pairwise LE.le xs → List.Pairwise LE.le (insert' a xs)
ordered : List.Pairwise LE.le (x :: xs)
h : ¬a ≤ x
⊢ (∀ a' ∈ insert' a xs, x ≤ a') ∧ List.Pairwise LE.le (insert' a xs)
case neg
α : Type
hl : LinearOrder α
inst✝ : DecidableRel LE.le
a x : α
xs : List α
ih : List.Pairwise LE.le xs → List.Pairwise LE.le (insert' a xs)
ordered : (∀ a' ∈ xs, x ≤ a') ∧ List.Pairwise LE.le xs
h : ¬a ≤ x
⊢ (∀ a' ∈ insert' a xs, x ≤ a') ∧ List.Pairwise LE.le (insert' a xs)