Module: Mathlib.CategoryTheory.GlueData

Goal state before:
pp: case none
C : Type u₁
inst✝⁵ : Category.{v, u₁} C
C' : Type u₂
inst✝⁴ : Category.{v, u₂} C'
D : GlueData C
F : C ⥤ C'
inst✝³ : HasMulticoequalizer D.diagram
inst✝² : PreservesColimit D.diagram.multispan F
inst✝¹ : ∀ (i j k : D.J), PreservesLimit (cospan (D.f i j) (D.f i k)) F
i j : D.J
inst✝ : ReflectsLimit (cospan (D.ι i) (D.ι j)) F
hc : IsLimit ((D.mapGlueData F).vPullbackCone i j)
e : cospan (F.map (D.ι i)) (F.map (D.ι j)) ≅ cospan ((D.mapGlueData F).ι i) ((D.mapGlueData F).ι j) :=
  NatIso.ofComponents
    (fun x ↦
      Option.casesOn (motive := fun t ↦
        x = t →
          ((cospan (F.map (D.ι i)) (F.map (D.ι j))).obj x ≅
            (cospan ((D.mapGlueData F).ι i) ((D.mapGlueData F).ι j)).obj x))
        x (fun h ↦ ⋯ ▸ D.gluedIso F)
        (fun val h ↦ ⋯ ▸ Iso.refl ((cospan (F.map (D.ι i)) (F.map (D.ι j))).obj (some val))) ⋯)
    ⋯
⊢ ((D.mapGlueData F).vPullbackCone i j).π.app none =
    (Iso.refl ((D.mapGlueData F).vPullbackCone i j).pt).hom ≫
      ((Cone.postcompose e.hom).obj (PullbackCone.mk (F.map (D.f i j)) (F.map (D.t i j ≫ D.f j i)) ⋯)).π.app none

pp: case some.left
C : Type u₁
inst✝⁵ : Category.{v, u₁} C
C' : Type u₂
inst✝⁴ : Category.{v, u₂} C'
D : GlueData C
F : C ⥤ C'
inst✝³ : HasMulticoequalizer D.diagram
inst✝² : PreservesColimit D.diagram.multispan F
inst✝¹ : ∀ (i j k : D.J), PreservesLimit (cospan (D.f i j) (D.f i k)) F
i j : D.J
inst✝ : ReflectsLimit (cospan (D.ι i) (D.ι j)) F
hc : IsLimit ((D.mapGlueData F).vPullbackCone i j)
e : cospan (F.map (D.ι i)) (F.map (D.ι j)) ≅ cospan ((D.mapGlueData F).ι i) ((D.mapGlueData F).ι j) :=
  NatIso.ofComponents
    (fun x ↦
      Option.casesOn (motive := fun t ↦
        x = t →
          ((cospan (F.map (D.ι i)) (F.map (D.ι j))).obj x ≅
            (cospan ((D.mapGlueData F).ι i) ((D.mapGlueData F).ι j)).obj x))
        x (fun h ↦ ⋯ ▸ D.gluedIso F)
        (fun val h ↦ ⋯ ▸ Iso.refl ((cospan (F.map (D.ι i)) (F.map (D.ι j))).obj (some val))) ⋯)
    ⋯
⊢ ((D.mapGlueData F).vPullbackCone i j).π.app (some WalkingPair.left) =
    (Iso.refl ((D.mapGlueData F).vPullbackCone i j).pt).hom ≫
      ((Cone.postcompose e.hom).obj (PullbackCone.mk (F.map (D.f i j)) (F.map (D.t i j ≫ D.f j i)) ⋯)).π.app
        (some WalkingPair.left)

pp: case some.right
C : Type u₁
inst✝⁵ : Category.{v, u₁} C
C' : Type u₂
inst✝⁴ : Category.{v, u₂} C'
D : GlueData C
F : C ⥤ C'
inst✝³ : HasMulticoequalizer D.diagram
inst✝² : PreservesColimit D.diagram.multispan F
inst✝¹ : ∀ (i j k : D.J), PreservesLimit (cospan (D.f i j) (D.f i k)) F
i j : D.J
inst✝ : ReflectsLimit (cospan (D.ι i) (D.ι j)) F
hc : IsLimit ((D.mapGlueData F).vPullbackCone i j)
e : cospan (F.map (D.ι i)) (F.map (D.ι j)) ≅ cospan ((D.mapGlueData F).ι i) ((D.mapGlueData F).ι j) :=
  NatIso.ofComponents
    (fun x ↦
      Option.casesOn (motive := fun t ↦
        x = t →
          ((cospan (F.map (D.ι i)) (F.map (D.ι j))).obj x ≅
            (cospan ((D.mapGlueData F).ι i) ((D.mapGlueData F).ι j)).obj x))
        x (fun h ↦ ⋯ ▸ D.gluedIso F)
        (fun val h ↦ ⋯ ▸ Iso.refl ((cospan (F.map (D.ι i)) (F.map (D.ι j))).obj (some val))) ⋯)
    ⋯
⊢ ((D.mapGlueData F).vPullbackCone i j).π.app (some WalkingPair.right) =
    (Iso.refl ((D.mapGlueData F).vPullbackCone i j).pt).hom ≫
      ((Cone.postcompose e.hom).obj (PullbackCone.mk (F.map (D.f i j)) (F.map (D.t i j ≫ D.f j i)) ⋯)).π.app
        (some WalkingPair.right)

Tactic:
all_goals simp [e]; rfl

Goal state after: