-- Mathlib/CategoryTheory/Localization/CalculusOfFractions.lean
lemma MorphismProperty.LeftFraction.map_eq_iff
    {X Y : C} (φ ψ : W.LeftFraction X Y) :
    φ.map L (Localization.inverts _ _) = ψ.map L (Localization.inverts _ _) ↔
      LeftFractionRel φ ψ

Proof state:
case mpr
C : Type u_1
D : Type u_2
inst✝³ : Category.{u_3, u_1} C
inst✝² : Category.{u_4, u_2} D
L : C ⥤ D
W : MorphismProperty C
inst✝¹ : L.IsLocalization W
inst✝ : W.HasLeftCalculusOfFractions
X Y : C
φ ψ : W.LeftFraction X Y
h : LeftFractionRel φ ψ
⊢ φ.map L ⋯ = ψ.map L ⋯

Tactic:
simp only [← Localization.Hom.map_mk _ L (Localization.inverts _ _)]

Result:
case mpr
C : Type u_1
D : Type u_2
inst✝³ : Category.{u_3, u_1} C
inst✝² : Category.{u_4, u_2} D
L : C ⥤ D
W : MorphismProperty C
inst✝¹ : L.IsLocalization W
inst✝ : W.HasLeftCalculusOfFractions
X Y : C
φ ψ : W.LeftFraction X Y
h : LeftFractionRel φ ψ
⊢ (Localization.Hom.mk φ).map L ⋯ = (Localization.Hom.mk ψ).map L ⋯

Proof state:
case mp
C : Type u_1
D : Type u_2
inst✝³ : Category.{u_3, u_1} C
inst✝² : Category.{u_4, u_2} D
L : C ⥤ D
W : MorphismProperty C
inst✝¹ : L.IsLocalization W
inst✝ : W.HasLeftCalculusOfFractions
X Y : C
φ ψ : W.LeftFraction X Y
h : φ.map L ⋯ = ψ.map L ⋯
⊢ φ.map (Localization.Q W) ⋯ = ψ.map (Localization.Q W) ⋯

Tactic:
apply map_eq_of_map_eq _ _ _ _ h

Result:
no goals

Proof state:
case mp
C : Type u_1
D : Type u_2
inst✝³ : Category.{u_3, u_1} C
inst✝² : Category.{u_4, u_2} D
L : C ⥤ D
W : MorphismProperty C
inst✝¹ : L.IsLocalization W
inst✝ : W.HasLeftCalculusOfFractions
X Y : C
φ ψ : W.LeftFraction X Y
h : φ.map L ⋯ = ψ.map L ⋯
⊢ LeftFractionRel φ ψ

Tactic:
rw [← MorphismProperty.LeftFraction.Localization.map_eq_iff]

Result:
case mp
C : Type u_1
D : Type u_2
inst✝³ : Category.{u_3, u_1} C
inst✝² : Category.{u_4, u_2} D
L : C ⥤ D
W : MorphismProperty C
inst✝¹ : L.IsLocalization W
inst✝ : W.HasLeftCalculusOfFractions
X Y : C
φ ψ : W.LeftFraction X Y
h : φ.map L ⋯ = ψ.map L ⋯
⊢ φ.map (Localization.Q W) ⋯ = ψ.map (Localization.Q W) ⋯

Proof state:
C : Type u_1
D : Type u_2
inst✝³ : Category.{u_3, u_1} C
inst✝² : Category.{u_4, u_2} D
L : C ⥤ D
W : MorphismProperty C
inst✝¹ : L.IsLocalization W
inst✝ : W.HasLeftCalculusOfFractions
X Y : C
φ ψ : W.LeftFraction X Y
⊢ φ.map L ⋯ = ψ.map L ⋯ ↔ LeftFractionRel φ ψ

Tactic:
constructor

Result:
case mp
C : Type u_1
D : Type u_2
inst✝³ : Category.{u_3, u_1} C
inst✝² : Category.{u_4, u_2} D
L : C ⥤ D
W : MorphismProperty C
inst✝¹ : L.IsLocalization W
inst✝ : W.HasLeftCalculusOfFractions
X Y : C
φ ψ : W.LeftFraction X Y
⊢ φ.map L ⋯ = ψ.map L ⋯ → LeftFractionRel φ ψ

case mpr
C : Type u_1
D : Type u_2
inst✝³ : Category.{u_3, u_1} C
inst✝² : Category.{u_4, u_2} D
L : C ⥤ D
W : MorphismProperty C
inst✝¹ : L.IsLocalization W
inst✝ : W.HasLeftCalculusOfFractions
X Y : C
φ ψ : W.LeftFraction X Y
⊢ LeftFractionRel φ ψ → φ.map L ⋯ = ψ.map L ⋯

Proof state:
case mpr
C : Type u_1
D : Type u_2
inst✝³ : Category.{u_3, u_1} C
inst✝² : Category.{u_4, u_2} D
L : C ⥤ D
W : MorphismProperty C
inst✝¹ : L.IsLocalization W
inst✝ : W.HasLeftCalculusOfFractions
X Y : C
φ ψ : W.LeftFraction X Y
h : LeftFractionRel φ ψ
⊢ (Localization.Hom.mk φ).map L ⋯ = (Localization.Hom.mk ψ).map L ⋯

Tactic:
congr 1

Result:
case mpr.e_f
C : Type u_1
D : Type u_2
inst✝³ : Category.{u_3, u_1} C
inst✝² : Category.{u_4, u_2} D
L : C ⥤ D
W : MorphismProperty C
inst✝¹ : L.IsLocalization W
inst✝ : W.HasLeftCalculusOfFractions
X Y : C
φ ψ : W.LeftFraction X Y
h : LeftFractionRel φ ψ
⊢ Localization.Hom.mk φ = Localization.Hom.mk ψ

Proof state:
case mp
C : Type u_1
D : Type u_2
inst✝³ : Category.{u_3, u_1} C
inst✝² : Category.{u_4, u_2} D
L : C ⥤ D
W : MorphismProperty C
inst✝¹ : L.IsLocalization W
inst✝ : W.HasLeftCalculusOfFractions
X Y : C
φ ψ : W.LeftFraction X Y
⊢ φ.map L ⋯ = ψ.map L ⋯ → LeftFractionRel φ ψ

Tactic:
intro h

Result:
case mp
C : Type u_1
D : Type u_2
inst✝³ : Category.{u_3, u_1} C
inst✝² : Category.{u_4, u_2} D
L : C ⥤ D
W : MorphismProperty C
inst✝¹ : L.IsLocalization W
inst✝ : W.HasLeftCalculusOfFractions
X Y : C
φ ψ : W.LeftFraction X Y
h : φ.map L ⋯ = ψ.map L ⋯
⊢ LeftFractionRel φ ψ

Proof state:
case mpr
C : Type u_1
D : Type u_2
inst✝³ : Category.{u_3, u_1} C
inst✝² : Category.{u_4, u_2} D
L : C ⥤ D
W : MorphismProperty C
inst✝¹ : L.IsLocalization W
inst✝ : W.HasLeftCalculusOfFractions
X Y : C
φ ψ : W.LeftFraction X Y
⊢ LeftFractionRel φ ψ → φ.map L ⋯ = ψ.map L ⋯

Tactic:
intro h

Result:
case mpr
C : Type u_1
D : Type u_2
inst✝³ : Category.{u_3, u_1} C
inst✝² : Category.{u_4, u_2} D
L : C ⥤ D
W : MorphismProperty C
inst✝¹ : L.IsLocalization W
inst✝ : W.HasLeftCalculusOfFractions
X Y : C
φ ψ : W.LeftFraction X Y
h : LeftFractionRel φ ψ
⊢ φ.map L ⋯ = ψ.map L ⋯

Proof state:
case mpr.e_f
C : Type u_1
D : Type u_2
inst✝³ : Category.{u_3, u_1} C
inst✝² : Category.{u_4, u_2} D
L : C ⥤ D
W : MorphismProperty C
inst✝¹ : L.IsLocalization W
inst✝ : W.HasLeftCalculusOfFractions
X Y : C
φ ψ : W.LeftFraction X Y
h : LeftFractionRel φ ψ
⊢ Localization.Hom.mk φ = Localization.Hom.mk ψ

Tactic:
exact Quot.sound h

Result:
no goals