-- Mathlib/Combinatorics/Quiver/Symmetric.lean
theorem lift_unique [HasReverse V'] (φ : V ⥤q V') (Φ : Symmetrify V ⥤q V') (hΦ : (of ⋙q Φ) = φ)
    (hΦinv : ∀ {X Y : Symmetrify V} (f : X ⟶ Y),
      Φ.map (Quiver.reverse f) = Quiver.reverse (Φ.map f)) :
    Φ = Symmetrify.lift φ

Proof state:
case h_map
V : Type u_2
inst✝² : Quiver V
V' : Type u_4
inst✝¹ : Quiver V'
inst✝ : HasReverse V'
Φ : Symmetrify V ⥤q V'
hΦinv : ∀ {X Y : Symmetrify V} (f : X ⟶ Y), Φ.map (reverse f) = reverse (Φ.map f)
X Y : Symmetrify V
f : X ⟶ Y
⊢ Φ.map f = Eq.recOn ⋯ (Eq.recOn ⋯ ((lift (of ⋙q Φ)).map f))

Tactic:
cases f

Result:
case h_map.inl
V : Type u_2
inst✝² : Quiver V
V' : Type u_4
inst✝¹ : Quiver V'
inst✝ : HasReverse V'
Φ : Symmetrify V ⥤q V'
hΦinv : ∀ {X Y : Symmetrify V} (f : X ⟶ Y), Φ.map (reverse f) = reverse (Φ.map f)
X Y : Symmetrify V
val✝ : X ⟶ Y
⊢ Φ.map (Sum.inl val✝) = Eq.recOn ⋯ (Eq.recOn ⋯ ((lift (of ⋙q Φ)).map (Sum.inl val✝)))

case h_map.inr
V : Type u_2
inst✝² : Quiver V
V' : Type u_4
inst✝¹ : Quiver V'
inst✝ : HasReverse V'
Φ : Symmetrify V ⥤q V'
hΦinv : ∀ {X Y : Symmetrify V} (f : X ⟶ Y), Φ.map (reverse f) = reverse (Φ.map f)
X Y : Symmetrify V
val✝ : Y ⟶ X
⊢ Φ.map (Sum.inr val✝) = Eq.recOn ⋯ (Eq.recOn ⋯ ((lift (of ⋙q Φ)).map (Sum.inr val✝)))

Proof state:
V : Type u_2
inst✝² : Quiver V
V' : Type u_4
inst✝¹ : Quiver V'
inst✝ : HasReverse V'
Φ : Symmetrify V ⥤q V'
hΦinv : ∀ {X Y : Symmetrify V} (f : X ⟶ Y), Φ.map (reverse f) = reverse (Φ.map f)
⊢ Φ = lift (of ⋙q Φ)

Tactic:
fapply Prefunctor.ext

Result:
case h_obj
V : Type u_2
inst✝² : Quiver V
V' : Type u_4
inst✝¹ : Quiver V'
inst✝ : HasReverse V'
Φ : Symmetrify V ⥤q V'
hΦinv : ∀ {X Y : Symmetrify V} (f : X ⟶ Y), Φ.map (reverse f) = reverse (Φ.map f)
⊢ ∀ (X : Symmetrify V), Φ.obj X = (lift (of ⋙q Φ)).obj X

case h_map
V : Type u_2
inst✝² : Quiver V
V' : Type u_4
inst✝¹ : Quiver V'
inst✝ : HasReverse V'
Φ : Symmetrify V ⥤q V'
hΦinv : ∀ {X Y : Symmetrify V} (f : X ⟶ Y), Φ.map (reverse f) = reverse (Φ.map f)
⊢ ∀ (X Y : Symmetrify V) (f : X ⟶ Y), Φ.map f = Eq.recOn ⋯ (Eq.recOn ⋯ ((lift (of ⋙q Φ)).map f))

Proof state:
case h_map
V : Type u_2
inst✝² : Quiver V
V' : Type u_4
inst✝¹ : Quiver V'
inst✝ : HasReverse V'
Φ : Symmetrify V ⥤q V'
hΦinv : ∀ {X Y : Symmetrify V} (f : X ⟶ Y), Φ.map (reverse f) = reverse (Φ.map f)
⊢ ∀ (X Y : Symmetrify V) (f : X ⟶ Y), Φ.map f = Eq.recOn ⋯ (Eq.recOn ⋯ ((lift (of ⋙q Φ)).map f))

Tactic:
rintro X Y f

Result:
case h_map
V : Type u_2
inst✝² : Quiver V
V' : Type u_4
inst✝¹ : Quiver V'
inst✝ : HasReverse V'
Φ : Symmetrify V ⥤q V'
hΦinv : ∀ {X Y : Symmetrify V} (f : X ⟶ Y), Φ.map (reverse f) = reverse (Φ.map f)
X Y : Symmetrify V
f : X ⟶ Y
⊢ Φ.map f = Eq.recOn ⋯ (Eq.recOn ⋯ ((lift (of ⋙q Φ)).map f))

Proof state:
case h_obj
V : Type u_2
inst✝² : Quiver V
V' : Type u_4
inst✝¹ : Quiver V'
inst✝ : HasReverse V'
Φ : Symmetrify V ⥤q V'
hΦinv : ∀ {X Y : Symmetrify V} (f : X ⟶ Y), Φ.map (reverse f) = reverse (Φ.map f)
⊢ ∀ (X : Symmetrify V), Φ.obj X = (lift (of ⋙q Φ)).obj X

Tactic:
rintro X

Result:
case h_obj
V : Type u_2
inst✝² : Quiver V
V' : Type u_4
inst✝¹ : Quiver V'
inst✝ : HasReverse V'
Φ : Symmetrify V ⥤q V'
hΦinv : ∀ {X Y : Symmetrify V} (f : X ⟶ Y), Φ.map (reverse f) = reverse (Φ.map f)
X : Symmetrify V
⊢ Φ.obj X = (lift (of ⋙q Φ)).obj X

Proof state:
V : Type u_2
inst✝² : Quiver V
V' : Type u_4
inst✝¹ : Quiver V'
inst✝ : HasReverse V'
φ : V ⥤q V'
Φ : Symmetrify V ⥤q V'
hΦ : of ⋙q Φ = φ
hΦinv : ∀ {X Y : Symmetrify V} (f : X ⟶ Y), Φ.map (reverse f) = reverse (Φ.map f)
⊢ Φ = lift φ

Tactic:
subst_vars

Result:
V : Type u_2
inst✝² : Quiver V
V' : Type u_4
inst✝¹ : Quiver V'
inst✝ : HasReverse V'
Φ : Symmetrify V ⥤q V'
hΦinv : ∀ {X Y : Symmetrify V} (f : X ⟶ Y), Φ.map (reverse f) = reverse (Φ.map f)
⊢ Φ = lift (of ⋙q Φ)

Proof state:
case h_map.inl
V : Type u_2
inst✝² : Quiver V
V' : Type u_4
inst✝¹ : Quiver V'
inst✝ : HasReverse V'
Φ : Symmetrify V ⥤q V'
hΦinv : ∀ {X Y : Symmetrify V} (f : X ⟶ Y), Φ.map (reverse f) = reverse (Φ.map f)
X Y : Symmetrify V
val✝ : X ⟶ Y
⊢ Φ.map (Sum.inl val✝) = Eq.recOn ⋯ (Eq.recOn ⋯ ((lift (of ⋙q Φ)).map (Sum.inl val✝)))

Tactic:
rfl

Result:
no goals

Proof state:
case h_map.inr
V : Type u_2
inst✝² : Quiver V
V' : Type u_4
inst✝¹ : Quiver V'
inst✝ : HasReverse V'
Φ : Symmetrify V ⥤q V'
hΦinv : ∀ {X Y : Symmetrify V} (f : X ⟶ Y), Φ.map (reverse f) = reverse (Φ.map f)
X Y : Symmetrify V
val✝ : Y ⟶ X
⊢ Φ.map (Sum.inr val✝) = Eq.recOn ⋯ (Eq.recOn ⋯ ((lift (of ⋙q Φ)).map (Sum.inr val✝)))

Tactic:
exact hΦinv (Sum.inl _)

Result:
no goals

Proof state:
case h_obj
V : Type u_2
inst✝² : Quiver V
V' : Type u_4
inst✝¹ : Quiver V'
inst✝ : HasReverse V'
Φ : Symmetrify V ⥤q V'
hΦinv : ∀ {X Y : Symmetrify V} (f : X ⟶ Y), Φ.map (reverse f) = reverse (Φ.map f)
X : Symmetrify V
⊢ Φ.obj X = (lift (of ⋙q Φ)).obj X

Tactic:
rfl

Result:
no goals