induction p with
| nil v => 
  simp [nil_toList]
  rw [concat, cons_toList, nil_toList]
| cons e p' ih =>
  simp [cons_toList, ih]
V : Type u
E : Type v
inst✝¹ : DecidableEq V
inst✝ : DecidableEq E
G✝ : Graph V E
u✝ v✝ w✝ : V
e✝ : EdgeBetween G✝ v✝ w✝
G : Graph V E
v w u : V
p : EdgePath G v w
e : EdgeBetween G w u
⊢ toList (concat p e) = List.concat (toList p) e.edge
no goals