(rw [← append_assoc])
case step
V : Type u
E : Type v
inst✝¹ : DecidableEq V
inst✝ : DecidableEq E
G : Graph V E
u✝¹ v✝ w✝ : V
e : EdgeBetween G v✝ w✝
v w u : V
a : EdgePath G v w
b₁ b₂ : EdgePath G w u
u✝ u'✝ : V
e✝ : EdgeBetween G u✝ u'✝
p₁✝ : EdgePath G w u✝
p₂✝ : EdgePath G u✝ u
⊢ [[a ++ p₁✝ ++ cons e✝ (cons (EdgeBetween.bar e✝) p₂✝)]] = [[a ++ (p₁✝ ++ p₂✝)]]
case step
V : Type u
E : Type v
inst✝¹ : DecidableEq V
inst✝ : DecidableEq E
G : Graph V E
u✝¹ v✝ w✝ : V
e : EdgeBetween G v✝ w✝
v w u : V
a : EdgePath G v w
b₁ b₂ : EdgePath G w u
u✝ u'✝ : V
e✝ : EdgeBetween G u✝ u'✝
p₁✝ : EdgePath G w u✝
p₂✝ : EdgePath G u✝ u
⊢ [[a ++ p₁✝ ++ cons e✝ (cons (EdgeBetween.bar e✝) p₂✝)]] = [[a ++ p₁✝ ++ p₂✝]]