-- Mathlib/CategoryTheory/Quotient.lean
theorem lift_unique (Φ : Quotient r ⥤ D) (hΦ : functor r ⋙ Φ = F) : Φ = lift r F H

Proof state:
C : Type u_3
inst✝¹ : Category.{u_1, u_3} C
r : HomRel C
D : Type u_4
inst✝ : Category.{u_2, u_4} D
Φ : Quotient r ⥤ D
H : ∀ (x y : C) (f₁ f₂ : x ⟶ y), r f₁ f₂ → (functor r ⋙ Φ).map f₁ = (functor r ⋙ Φ).map f₂
⊢ Φ = lift r (functor r ⋙ Φ) H

Tactic:
fapply Functor.hext

Result:
case h_obj
C : Type u_3
inst✝¹ : Category.{u_1, u_3} C
r : HomRel C
D : Type u_4
inst✝ : Category.{u_2, u_4} D
Φ : Quotient r ⥤ D
H : ∀ (x y : C) (f₁ f₂ : x ⟶ y), r f₁ f₂ → (functor r ⋙ Φ).map f₁ = (functor r ⋙ Φ).map f₂
⊢ ∀ (X : Quotient r), Φ.obj X = (lift r (functor r ⋙ Φ) H).obj X

case h_map
C : Type u_3
inst✝¹ : Category.{u_1, u_3} C
r : HomRel C
D : Type u_4
inst✝ : Category.{u_2, u_4} D
Φ : Quotient r ⥤ D
H : ∀ (x y : C) (f₁ f₂ : x ⟶ y), r f₁ f₂ → (functor r ⋙ Φ).map f₁ = (functor r ⋙ Φ).map f₂
⊢ ∀ (X Y : Quotient r) (f : X ⟶ Y), HEq (Φ.map f) ((lift r (functor r ⋙ Φ) H).map f)

Proof state:
case h_obj
C : Type u_3
inst✝¹ : Category.{u_1, u_3} C
r : HomRel C
D : Type u_4
inst✝ : Category.{u_2, u_4} D
Φ : Quotient r ⥤ D
H : ∀ (x y : C) (f₁ f₂ : x ⟶ y), r f₁ f₂ → (functor r ⋙ Φ).map f₁ = (functor r ⋙ Φ).map f₂
X : Quotient r
⊢ Φ.obj X = Φ.obj ((functor r).obj X.as)

Tactic:
congr

Result:
no goals

Proof state:
case h_obj
C : Type u_3
inst✝¹ : Category.{u_1, u_3} C
r : HomRel C
D : Type u_4
inst✝ : Category.{u_2, u_4} D
Φ : Quotient r ⥤ D
H : ∀ (x y : C) (f₁ f₂ : x ⟶ y), r f₁ f₂ → (functor r ⋙ Φ).map f₁ = (functor r ⋙ Φ).map f₂
⊢ ∀ (X : Quotient r), Φ.obj X = (lift r (functor r ⋙ Φ) H).obj X

Tactic:
rintro X

Result:
case h_obj
C : Type u_3
inst✝¹ : Category.{u_1, u_3} C
r : HomRel C
D : Type u_4
inst✝ : Category.{u_2, u_4} D
Φ : Quotient r ⥤ D
H : ∀ (x y : C) (f₁ f₂ : x ⟶ y), r f₁ f₂ → (functor r ⋙ Φ).map f₁ = (functor r ⋙ Φ).map f₂
X : Quotient r
⊢ Φ.obj X = (lift r (functor r ⋙ Φ) H).obj X

Proof state:
C : Type u_3
inst✝¹ : Category.{u_1, u_3} C
r : HomRel C
D : Type u_4
inst✝ : Category.{u_2, u_4} D
F : C ⥤ D
H : ∀ (x y : C) (f₁ f₂ : x ⟶ y), r f₁ f₂ → F.map f₁ = F.map f₂
Φ : Quotient r ⥤ D
hΦ : functor r ⋙ Φ = F
⊢ Φ = lift r F H

Tactic:
subst_vars

Result:
C : Type u_3
inst✝¹ : Category.{u_1, u_3} C
r : HomRel C
D : Type u_4
inst✝ : Category.{u_2, u_4} D
Φ : Quotient r ⥤ D
H : ∀ (x y : C) (f₁ f₂ : x ⟶ y), r f₁ f₂ → (functor r ⋙ Φ).map f₁ = (functor r ⋙ Φ).map f₂
⊢ Φ = lift r (functor r ⋙ Φ) H

Proof state:
case h_obj
C : Type u_3
inst✝¹ : Category.{u_1, u_3} C
r : HomRel C
D : Type u_4
inst✝ : Category.{u_2, u_4} D
Φ : Quotient r ⥤ D
H : ∀ (x y : C) (f₁ f₂ : x ⟶ y), r f₁ f₂ → (functor r ⋙ Φ).map f₁ = (functor r ⋙ Φ).map f₂
X : Quotient r
⊢ Φ.obj X = (lift r (functor r ⋙ Φ) H).obj X

Tactic:
dsimp [lift, Functor]

Result:
case h_obj
C : Type u_3
inst✝¹ : Category.{u_1, u_3} C
r : HomRel C
D : Type u_4
inst✝ : Category.{u_2, u_4} D
Φ : Quotient r ⥤ D
H : ∀ (x y : C) (f₁ f₂ : x ⟶ y), r f₁ f₂ → (functor r ⋙ Φ).map f₁ = (functor r ⋙ Φ).map f₂
X : Quotient r
⊢ Φ.obj X = Φ.obj ((functor r).obj X.as)

Proof state:
case h_map
C : Type u_3
inst✝¹ : Category.{u_1, u_3} C
r : HomRel C
D : Type u_4
inst✝ : Category.{u_2, u_4} D
Φ : Quotient r ⥤ D
H : ∀ (x y : C) (f₁ f₂ : x ⟶ y), r f₁ f₂ → (functor r ⋙ Φ).map f₁ = (functor r ⋙ Φ).map f₂
X✝ Y✝ : Quotient r
f : X✝ ⟶ Y✝
x✝ : X✝.as ⟶ Y✝.as
⊢ HEq (Φ.map (Quot.mk (CompClosure r) x✝)) ((Quot.mk (CompClosure r) x✝).liftOn (fun f => Φ.map ((functor r).map f)) ⋯)

Tactic:
simp only [heq_eq_eq]

Result:
case h_map
C : Type u_3
inst✝¹ : Category.{u_1, u_3} C
r : HomRel C
D : Type u_4
inst✝ : Category.{u_2, u_4} D
Φ : Quotient r ⥤ D
H : ∀ (x y : C) (f₁ f₂ : x ⟶ y), r f₁ f₂ → (functor r ⋙ Φ).map f₁ = (functor r ⋙ Φ).map f₂
X✝ Y✝ : Quotient r
f : X✝ ⟶ Y✝
x✝ : X✝.as ⟶ Y✝.as
⊢ Φ.map (Quot.mk (CompClosure r) x✝) = (Quot.mk (CompClosure r) x✝).liftOn (fun f => Φ.map ((functor r).map f)) ⋯

Proof state:
case h_map
C : Type u_3
inst✝¹ : Category.{u_1, u_3} C
r : HomRel C
D : Type u_4
inst✝ : Category.{u_2, u_4} D
Φ : Quotient r ⥤ D
H : ∀ (x y : C) (f₁ f₂ : x ⟶ y), r f₁ f₂ → (functor r ⋙ Φ).map f₁ = (functor r ⋙ Φ).map f₂
X✝ Y✝ : Quotient r
f : X✝ ⟶ Y✝
⊢ HEq (Φ.map f) (Quot.liftOn f (fun f => Φ.map ((functor r).map f)) ⋯)

Tactic:
refine Quot.inductionOn f (fun _ ↦ ?_)

Result:
case h_map
C : Type u_3
inst✝¹ : Category.{u_1, u_3} C
r : HomRel C
D : Type u_4
inst✝ : Category.{u_2, u_4} D
Φ : Quotient r ⥤ D
H : ∀ (x y : C) (f₁ f₂ : x ⟶ y), r f₁ f₂ → (functor r ⋙ Φ).map f₁ = (functor r ⋙ Φ).map f₂
X✝ Y✝ : Quotient r
f : X✝ ⟶ Y✝
x✝ : X✝.as ⟶ Y✝.as
⊢ HEq (Φ.map (Quot.mk (CompClosure r) x✝)) ((Quot.mk (CompClosure r) x✝).liftOn (fun f => Φ.map ((functor r).map f)) ⋯)

Proof state:
case h_map
C : Type u_3
inst✝¹ : Category.{u_1, u_3} C
r : HomRel C
D : Type u_4
inst✝ : Category.{u_2, u_4} D
Φ : Quotient r ⥤ D
H : ∀ (x y : C) (f₁ f₂ : x ⟶ y), r f₁ f₂ → (functor r ⋙ Φ).map f₁ = (functor r ⋙ Φ).map f₂
⊢ ∀ (X Y : Quotient r) (f : X ⟶ Y), HEq (Φ.map f) ((lift r (functor r ⋙ Φ) H).map f)

Tactic:
rintro _ _ f

Result:
case h_map
C : Type u_3
inst✝¹ : Category.{u_1, u_3} C
r : HomRel C
D : Type u_4
inst✝ : Category.{u_2, u_4} D
Φ : Quotient r ⥤ D
H : ∀ (x y : C) (f₁ f₂ : x ⟶ y), r f₁ f₂ → (functor r ⋙ Φ).map f₁ = (functor r ⋙ Φ).map f₂
X✝ Y✝ : Quotient r
f : X✝ ⟶ Y✝
⊢ HEq (Φ.map f) ((lift r (functor r ⋙ Φ) H).map f)

Proof state:
case h_map
C : Type u_3
inst✝¹ : Category.{u_1, u_3} C
r : HomRel C
D : Type u_4
inst✝ : Category.{u_2, u_4} D
Φ : Quotient r ⥤ D
H : ∀ (x y : C) (f₁ f₂ : x ⟶ y), r f₁ f₂ → (functor r ⋙ Φ).map f₁ = (functor r ⋙ Φ).map f₂
X✝ Y✝ : Quotient r
f : X✝ ⟶ Y✝
⊢ HEq (Φ.map f) ((lift r (functor r ⋙ Φ) H).map f)

Tactic:
dsimp [lift, Functor]

Result:
case h_map
C : Type u_3
inst✝¹ : Category.{u_1, u_3} C
r : HomRel C
D : Type u_4
inst✝ : Category.{u_2, u_4} D
Φ : Quotient r ⥤ D
H : ∀ (x y : C) (f₁ f₂ : x ⟶ y), r f₁ f₂ → (functor r ⋙ Φ).map f₁ = (functor r ⋙ Φ).map f₂
X✝ Y✝ : Quotient r
f : X✝ ⟶ Y✝
⊢ HEq (Φ.map f) (Quot.liftOn f (fun f => Φ.map ((functor r).map f)) ⋯)

Proof state:
case h_map
C : Type u_3
inst✝¹ : Category.{u_1, u_3} C
r : HomRel C
D : Type u_4
inst✝ : Category.{u_2, u_4} D
Φ : Quotient r ⥤ D
H : ∀ (x y : C) (f₁ f₂ : x ⟶ y), r f₁ f₂ → (functor r ⋙ Φ).map f₁ = (functor r ⋙ Φ).map f₂
X✝ Y✝ : Quotient r
f : X✝ ⟶ Y✝
x✝ : X✝.as ⟶ Y✝.as
⊢ Φ.map (Quot.mk (CompClosure r) x✝) = (Quot.mk (CompClosure r) x✝).liftOn (fun f => Φ.map ((functor r).map f)) ⋯

Tactic:
congr

Result:
no goals