intro x y xs hneq
α : Type u_1
inst✝ : DecidableEq α
⊢ ∀ (x y : α) (xs : List α), x ≠ y → removeAllEq (x :: xs) [y] = x :: removeAllEq xs [y]
α : Type u_1
inst✝ : DecidableEq α
x y : α
xs : List α
hneq : x ≠ y
⊢ removeAllEq (x :: xs) [y] = x :: removeAllEq xs [y]