exact h1 x e.fst ih_4 e.snd ih_2 ih_1
α : Type
inst : DecidableEq α
g : Graph α
xs : List α
h1 : ∀ (a x : α), x ∈ xs → ∀ (x_1 : List α), a ∈ x_1 → (x, x_1) ∈ g → a ∈ xs
a x : α
e : α × List α
ih_1 : e ∈ g
ih_2 : x ∈ e.2
a✝ : reachable_from_list g xs e.1
ih_4 : e.1 ∈ xs
⊢ x ∈ xs
no goals