mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.CategoryTheory.Limits.Shapes.Pullback.HasPullback

Goal state before:
pp: C : Type u
inst✝³ : Category.{v, u} C
X Y Z : C
D : Type u₂
inst✝² : Category.{v₂, u₂} D
G : C ⥤ D
f : X ⟶ Y
g : X ⟶ Z
inst✝¹ : HasPushout f g
inst✝ : HasPushout (G.map f) (G.map g)
W : C
h : Y ⟶ W
k : Z ⟶ W
w : f ≫ h = g ≫ k
⊢ pushoutComparison G f g ≫ G.map (pushout.desc h k w) = pushout.desc (G.map h) (G.map k) ⋯

Tactic:
ext <;> simp [← G.map_comp]

Goal state after:
Module: Mathlib.CategoryTheory.Limits.Shapes.Pullback.HasPullback

Goal state before:
pp: C : Type u
inst✝³ : Category.{v, u} C
X Y : C
f : X ⟶ Y
Z : C
inst✝² : HasBinaryProduct Z Y
inst✝¹ : HasBinaryProduct Z X
inst✝ : HasPullback prod.snd f
⊢ (pullbackProdSndIsoProd f Z).hom ≫ prod.fst = pullback.fst prod.snd f ≫ prod.fst

Tactic:
by
  simp [pullbackProdSndIsoProd]

Goal state after:
Module: Mathlib.CategoryTheory.Limits.Shapes.Pullback.HasPullback

Goal state before:
pp: C : Type u
inst✝³ : Category.{v, u} C
X Y : C
f : X ⟶ Y
Z : C
inst✝² : HasBinaryProduct Z Y
inst✝¹ : HasBinaryProduct Z X
inst✝ : HasPullback prod.snd f
⊢ (pullbackProdSndIsoProd f Z).hom ≫ prod.snd = pullback.snd prod.snd f

Tactic:
by
  simp [pullbackProdSndIsoProd]

Goal state after:
Module: Mathlib.CategoryTheory.Limits.Shapes.Pullback.HasPullback

Goal state before:
pp: C : Type u
inst✝³ : Category.{v, u} C
X Y : C
f : X ⟶ Y
Z : C
inst✝² : HasBinaryProduct Z Y
inst✝¹ : HasBinaryProduct Z X
inst✝ : HasPullback prod.snd f
⊢ (pullbackProdSndIsoProd f Z).inv ≫ pullback.fst prod.snd f ≫ prod.fst = prod.fst

Tactic:
by
  simp [pullbackProdSndIsoProd]

Goal state after:
Module: Mathlib.CategoryTheory.Limits.Shapes.Pullback.HasPullback

Goal state before:
pp: C : Type u
inst✝³ : Category.{v, u} C
X Y : C
f : X ⟶ Y
Z : C
inst✝² : HasBinaryProduct Z Y
inst✝¹ : HasBinaryProduct Z X
inst✝ : HasPullback prod.snd f
⊢ (pullbackProdSndIsoProd f Z).inv ≫ pullback.fst prod.snd f ≫ prod.snd = prod.snd ≫ f

Tactic:
by
  simp [pullbackProdSndIsoProd]

Goal state after:
Module: Mathlib.CategoryTheory.Limits.Shapes.Pullback.HasPullback

Goal state before:
pp: C : Type u
inst✝³ : Category.{v, u} C
X Y : C
f : X ⟶ Y
Z : C
inst✝² : HasBinaryProduct Z Y
inst✝¹ : HasBinaryProduct Z X
inst✝ : HasPullback prod.snd f
⊢ (pullbackProdSndIsoProd f Z).inv ≫ pullback.snd prod.snd f = prod.snd

Tactic:
by
  simp [pullbackProdSndIsoProd]

Goal state after:
Module: Mathlib.CategoryTheory.Limits.Shapes.Equalizers

Goal state before:
pp: C : Type u
X Y : C
inst✝ : Category.{v, u} C
f g : X ⟶ Y
s : Fork f g
⊢ s.π.app one = s.π.app zero ≫ g

Tactic:
← s.w right,

Goal state after:
C : Type u
X Y : C
inst✝ : Category.{v, u} C
f g : X ⟶ Y
s : Fork f g
⊢ s.π.app zero ≫ (parallelPair f g).map right = s.π.app zero ≫ g
Module: Mathlib.CategoryTheory.Limits.Shapes.Equalizers

Goal state before:
pp: C : Type u
X Y : C
inst✝ : Category.{v, u} C
f g : X ⟶ Y
s : Cofork f g
⊢ s.ι.app zero = g ≫ s.ι.app one

Tactic:
← s.w right,

Goal state after:
C : Type u
X Y : C
inst✝ : Category.{v, u} C
f g : X ⟶ Y
s : Cofork f g
⊢ (parallelPair f g).map right ≫ s.ι.app one = g ≫ s.ι.app one
Module: Mathlib.Algebra.Category.ModuleCat.Semi

Goal state before:
pp: R : Type u
inst✝ : Semiring R
M : SemimoduleCat R
h : IsZero M
x : ↑M
⊢ x = 0

Tactic:
← LinearMap.id_apply (R := R) x,

Goal state after:
R : Type u
inst✝ : Semiring R
M : SemimoduleCat R
h : IsZero M
x : ↑M
⊢ LinearMap.id x = 0
Module: Mathlib.CategoryTheory.Limits.Preserves.Basic

Goal state before:
pp: case mk
C : Type u₁
inst✝² : Category.{v₁, u₁} C
D : Type u₂
inst✝¹ : Category.{v₂, u₂} D
J✝ : Type w
inst✝ : Category.{w', w} J✝
K : J✝ ⥤ C
J : Type w
𝒥 : Category.{w', w} J
obj✝ : J → C
map✝ : {X Y : J} → (X ⟶ Y) → (obj✝ X ⟶ obj✝ Y)
map_id✝ : ∀ (X : J), map✝ (𝟙 X) = 𝟙 (obj✝ X)
map_comp✝ : ∀ {X Y Z : J} (f : X ⟶ Y) (g : Y ⟶ Z), map✝ (f ≫ g) = map✝ f ≫ map✝ g
pt✝ : C
app✝ :
  (X : J) →
    ((Functor.const J).obj pt✝).obj X ⟶ { obj := obj✝, map := map✝, map_id := map_id✝, map_comp := map_comp✝ }.obj X
naturality✝ :
  ∀ ⦃X Y : J⦄ (f : X ⟶ Y),
    ((Functor.const J).obj pt✝).map f ≫ app✝ Y =
      app✝ X ≫ { obj := obj✝, map := map✝, map_id := map_id✝, map_comp := map_comp✝ }.map f
h : IsLimit { pt := pt✝, π := { app := app✝, naturality := naturality✝ } }
s : Cone ({ obj := obj✝, map := map✝, map_id := map_id✝, map_comp := map_comp✝ } ⋙ 𝟭 C)
⊢ ∀ (j : J),
    h.lift { pt := s.pt, π := { app := fun j ↦ s.π.app j, naturality := ⋯ } } ≫
        ((𝟭 C).mapCone { pt := pt✝, π := { app := app✝, naturality := naturality✝ } }).π.app j =
      s.π.app j

Tactic:
j

Goal state after:
case mk
C : Type u₁
inst✝² : Category.{v₁, u₁} C
D : Type u₂
inst✝¹ : Category.{v₂, u₂} D
J✝ : Type w
inst✝ : Category.{w', w} J✝
K : J✝ ⥤ C
J : Type w
𝒥 : Category.{w', w} J
obj✝ : J → C
map✝ : {X Y : J} → (X ⟶ Y) → (obj✝ X ⟶ obj✝ Y)
map_id✝ : ∀ (X : J), map✝ (𝟙 X) = 𝟙 (obj✝ X)
map_comp✝ : ∀ {X Y Z : J} (f : X ⟶ Y) (g : Y ⟶ Z), map✝ (f ≫ g) = map✝ f ≫ map✝ g
pt✝ : C
app✝ :
  (X : J) →
    ((Functor.const J).obj pt✝).obj X ⟶ { obj := obj✝, map := map✝, map_id := map_id✝, map_comp := map_comp✝ }.obj X
naturality✝ :
  ∀ ⦃X Y : J⦄ (f : X ⟶ Y),
    ((Functor.const J).obj pt✝).map f ≫ app✝ Y =
      app✝ X ≫ { obj := obj✝, map := map✝, map_id := map_id✝, map_comp := map_comp✝ }.map f
h : IsLimit { pt := pt✝, π := { app := app✝, naturality := naturality✝ } }
s : Cone ({ obj := obj✝, map := map✝, map_id := map_id✝, map_comp := map_comp✝ } ⋙ 𝟭 C)
j : J
⊢ h.lift { pt := s.pt, π := { app := fun j ↦ s.π.app j, naturality := ⋯ } } ≫
      ((𝟭 C).mapCone { pt := pt✝, π := { app := app✝, naturality := naturality✝ } }).π.app j =
    s.π.app j
Module: Mathlib.CategoryTheory.Limits.Shapes.ZeroMorphisms

Goal state before:
pp: case mpr
C : Type u
inst✝² : Category.{v, u} C
inst✝¹ : HasZeroMorphisms C
X Y : C
f : X ⟶ Y
inst✝ : IsSplitEpi f
⊢ f = 0 → 𝟙 Y = 0

Tactic:
intro h
    rw [← IsSplitEpi.id f]
    simp [h]

Goal state after:
Module: Mathlib.CategoryTheory.Limits.Preserves.Basic

Goal state before:
pp: case mk
C : Type u₁
inst✝² : Category.{v₁, u₁} C
D : Type u₂
inst✝¹ : Category.{v₂, u₂} D
J✝ : Type w
inst✝ : Category.{w', w} J✝
K : J✝ ⥤ C
J : Type w
𝒥 : Category.{w', w} J
obj✝ : J → C
map✝ : {X Y : J} → (X ⟶ Y) → (obj✝ X ⟶ obj✝ Y)
map_id✝ : ∀ (X : J), map✝ (𝟙 X) = 𝟙 (obj✝ X)
map_comp✝ : ∀ {X Y Z : J} (f : X ⟶ Y) (g : Y ⟶ Z), map✝ (f ≫ g) = map✝ f ≫ map✝ g
pt✝ : C
app✝ :
  (X : J) →
    { obj := obj✝, map := map✝, map_id := map_id✝, map_comp := map_comp✝ }.obj X ⟶ ((Functor.const J).obj pt✝).obj X
naturality✝ :
  ∀ ⦃X Y : J⦄ (f : X ⟶ Y),
    { obj := obj✝, map := map✝, map_id := map_id✝, map_comp := map_comp✝ }.map f ≫ app✝ Y =
      app✝ X ≫ ((Functor.const J).obj pt✝).map f
h : IsColimit { pt := pt✝, ι := { app := app✝, naturality := naturality✝ } }
s : Cocone ({ obj := obj✝, map := map✝, map_id := map_id✝, map_comp := map_comp✝ } ⋙ 𝟭 C)
⊢ ∀ (j : J),
    ((𝟭 C).mapCocone { pt := pt✝, ι := { app := app✝, naturality := naturality✝ } }).ι.app j ≫
        h.desc { pt := s.pt, ι := { app := fun j ↦ s.ι.app j, naturality := ⋯ } } =
      s.ι.app j

Tactic:
j

Goal state after:
case mk
C : Type u₁
inst✝² : Category.{v₁, u₁} C
D : Type u₂
inst✝¹ : Category.{v₂, u₂} D
J✝ : Type w
inst✝ : Category.{w', w} J✝
K : J✝ ⥤ C
J : Type w
𝒥 : Category.{w', w} J
obj✝ : J → C
map✝ : {X Y : J} → (X ⟶ Y) → (obj✝ X ⟶ obj✝ Y)
map_id✝ : ∀ (X : J), map✝ (𝟙 X) = 𝟙 (obj✝ X)
map_comp✝ : ∀ {X Y Z : J} (f : X ⟶ Y) (g : Y ⟶ Z), map✝ (f ≫ g) = map✝ f ≫ map✝ g
pt✝ : C
app✝ :
  (X : J) →
    { obj := obj✝, map := map✝, map_id := map_id✝, map_comp := map_comp✝ }.obj X ⟶ ((Functor.const J).obj pt✝).obj X
naturality✝ :
  ∀ ⦃X Y : J⦄ (f : X ⟶ Y),
    { obj := obj✝, map := map✝, map_id := map_id✝, map_comp := map_comp✝ }.map f ≫ app✝ Y =
      app✝ X ≫ ((Functor.const J).obj pt✝).map f
h : IsColimit { pt := pt✝, ι := { app := app✝, naturality := naturality✝ } }
s : Cocone ({ obj := obj✝, map := map✝, map_id := map_id✝, map_comp := map_comp✝ } ⋙ 𝟭 C)
j : J
⊢ ((𝟭 C).mapCocone { pt := pt✝, ι := { app := app✝, naturality := naturality✝ } }).ι.app j ≫
      h.desc { pt := s.pt, ι := { app := fun j ↦ s.ι.app j, naturality := ⋯ } } =
    s.ι.app j
Module: Mathlib.CategoryTheory.Limits.Shapes.Equalizers

Goal state before:
pp: C : Type u
X Y : C
inst✝³ : Category.{v, u} C
f g : X ⟶ Y
D : Type u₂
inst✝² : Category.{v₂, u₂} D
G : C ⥤ D
inst✝¹ : HasCoequalizer f g
inst✝ : HasCoequalizer (G.map f) (G.map g)
⊢ G.map f ≫ G.map (coequalizer.π f g) = G.map g ≫ G.map (coequalizer.π f g)

Tactic:
by simp only [← G.map_comp]; rw [coequalizer.condition]

Goal state after:
Module: Mathlib.CategoryTheory.Limits.Shapes.Equalizers

Goal state before:
pp: C : Type u
X✝ Y : C
inst✝ : Category.{v, u} C
f✝ g : X✝ ⟶ Y
X : C
f : X ⟶ X
hf : f ≫ f = f
c : Fork (𝟙 X) f
i : IsLimit c
this : Mono c.ι := mono_of_isLimit_fork i
⊢ c.ι ≫ 𝟙 X = c.ι

Tactic:
exact Category.comp_id c.ι

Goal state after:
Module: Mathlib.CategoryTheory.Limits.Preserves.Basic

Goal state before:
pp: case mk
C : Type u₁
inst✝² : Category.{v₁, u₁} C
D : Type u₂
inst✝¹ : Category.{v₂, u₂} D
J✝ : Type w
inst✝ : Category.{w', w} J✝
K : J✝ ⥤ C
J : Type w'
𝒥 : Category.{w, w'} J
obj✝ : J → C
map✝ : {X Y : J} → (X ⟶ Y) → (obj✝ X ⟶ obj✝ Y)
map_id✝ : ∀ (X : J), map✝ (𝟙 X) = 𝟙 (obj✝ X)
map_comp✝ : ∀ {X Y Z : J} (f : X ⟶ Y) (g : Y ⟶ Z), map✝ (f ≫ g) = map✝ f ≫ map✝ g
pt✝ : C
app✝ :
  (X : J) →
    ((Functor.const J).obj pt✝).obj X ⟶ { obj := obj✝, map := map✝, map_id := map_id✝, map_comp := map_comp✝ }.obj X
naturality✝ :
  ∀ ⦃X Y : J⦄ (f : X ⟶ Y),
    ((Functor.const J).obj pt✝).map f ≫ app✝ Y =
      app✝ X ≫ { obj := obj✝, map := map✝, map_id := map_id✝, map_comp := map_comp✝ }.map f
h : IsLimit ((𝟭 C).mapCone { pt := pt✝, π := { app := app✝, naturality := naturality✝ } })
s : Cone { obj := obj✝, map := map✝, map_id := map_id✝, map_comp := map_comp✝ }
⊢ ∀ (j : J),
    h.lift { pt := s.pt, π := { app := fun j ↦ s.π.app j, naturality := ⋯ } } ≫
        { pt := pt✝, π := { app := app✝, naturality := naturality✝ } }.π.app j =
      s.π.app j

Tactic:
j

Goal state after:
case mk
C : Type u₁
inst✝² : Category.{v₁, u₁} C
D : Type u₂
inst✝¹ : Category.{v₂, u₂} D
J✝ : Type w
inst✝ : Category.{w', w} J✝
K : J✝ ⥤ C
J : Type w'
𝒥 : Category.{w, w'} J
obj✝ : J → C
map✝ : {X Y : J} → (X ⟶ Y) → (obj✝ X ⟶ obj✝ Y)
map_id✝ : ∀ (X : J), map✝ (𝟙 X) = 𝟙 (obj✝ X)
map_comp✝ : ∀ {X Y Z : J} (f : X ⟶ Y) (g : Y ⟶ Z), map✝ (f ≫ g) = map✝ f ≫ map✝ g
pt✝ : C
app✝ :
  (X : J) →
    ((Functor.const J).obj pt✝).obj X ⟶ { obj := obj✝, map := map✝, map_id := map_id✝, map_comp := map_comp✝ }.obj X
naturality✝ :
  ∀ ⦃X Y : J⦄ (f : X ⟶ Y),
    ((Functor.const J).obj pt✝).map f ≫ app✝ Y =
      app✝ X ≫ { obj := obj✝, map := map✝, map_id := map_id✝, map_comp := map_comp✝ }.map f
h : IsLimit ((𝟭 C).mapCone { pt := pt✝, π := { app := app✝, naturality := naturality✝ } })
s : Cone { obj := obj✝, map := map✝, map_id := map_id✝, map_comp := map_comp✝ }
j : J
⊢ h.lift { pt := s.pt, π := { app := fun j ↦ s.π.app j, naturality := ⋯ } } ≫
      { pt := pt✝, π := { app := app✝, naturality := naturality✝ } }.π.app j =
    s.π.app j
Module: Mathlib.CategoryTheory.Limits.Preserves.Basic

Goal state before:
pp: case mk
C : Type u₁
inst✝² : Category.{v₁, u₁} C
D : Type u₂
inst✝¹ : Category.{v₂, u₂} D
J✝ : Type w
inst✝ : Category.{w', w} J✝
K : J✝ ⥤ C
J : Type w'
𝒥 : Category.{w, w'} J
obj✝ : J → C
map✝ : {X Y : J} → (X ⟶ Y) → (obj✝ X ⟶ obj✝ Y)
map_id✝ : ∀ (X : J), map✝ (𝟙 X) = 𝟙 (obj✝ X)
map_comp✝ : ∀ {X Y Z : J} (f : X ⟶ Y) (g : Y ⟶ Z), map✝ (f ≫ g) = map✝ f ≫ map✝ g
pt✝ : C
app✝ :
  (X : J) →
    { obj := obj✝, map := map✝, map_id := map_id✝, map_comp := map_comp✝ }.obj X ⟶ ((Functor.const J).obj pt✝).obj X
naturality✝ :
  ∀ ⦃X Y : J⦄ (f : X ⟶ Y),
    { obj := obj✝, map := map✝, map_id := map_id✝, map_comp := map_comp✝ }.map f ≫ app✝ Y =
      app✝ X ≫ ((Functor.const J).obj pt✝).map f
h : IsColimit ((𝟭 C).mapCocone { pt := pt✝, ι := { app := app✝, naturality := naturality✝ } })
s : Cocone { obj := obj✝, map := map✝, map_id := map_id✝, map_comp := map_comp✝ }
⊢ ∀ (j : J),
    { pt := pt✝, ι := { app := app✝, naturality := naturality✝ } }.ι.app j ≫
        h.desc { pt := s.pt, ι := { app := fun j ↦ s.ι.app j, naturality := ⋯ } } =
      s.ι.app j

Tactic:
j

Goal state after:
case mk
C : Type u₁
inst✝² : Category.{v₁, u₁} C
D : Type u₂
inst✝¹ : Category.{v₂, u₂} D
J✝ : Type w
inst✝ : Category.{w', w} J✝
K : J✝ ⥤ C
J : Type w'
𝒥 : Category.{w, w'} J
obj✝ : J → C
map✝ : {X Y : J} → (X ⟶ Y) → (obj✝ X ⟶ obj✝ Y)
map_id✝ : ∀ (X : J), map✝ (𝟙 X) = 𝟙 (obj✝ X)
map_comp✝ : ∀ {X Y Z : J} (f : X ⟶ Y) (g : Y ⟶ Z), map✝ (f ≫ g) = map✝ f ≫ map✝ g
pt✝ : C
app✝ :
  (X : J) →
    { obj := obj✝, map := map✝, map_id := map_id✝, map_comp := map_comp✝ }.obj X ⟶ ((Functor.const J).obj pt✝).obj X
naturality✝ :
  ∀ ⦃X Y : J⦄ (f : X ⟶ Y),
    { obj := obj✝, map := map✝, map_id := map_id✝, map_comp := map_comp✝ }.map f ≫ app✝ Y =
      app✝ X ≫ ((Functor.const J).obj pt✝).map f
h : IsColimit ((𝟭 C).mapCocone { pt := pt✝, ι := { app := app✝, naturality := naturality✝ } })
s : Cocone { obj := obj✝, map := map✝, map_id := map_id✝, map_comp := map_comp✝ }
j : J
⊢ { pt := pt✝, ι := { app := app✝, naturality := naturality✝ } }.ι.app j ≫
      h.desc { pt := s.pt, ι := { app := fun j ↦ s.ι.app j, naturality := ⋯ } } =
    s.ι.app j
Module: Mathlib.CategoryTheory.Linear.Basic

Goal state before:
pp: C : Type u
inst✝¹ : Category.{v, u} C
inst✝ : Preadditive C
X _Y _Z : C
r : ℤ
f : X ⟶ _Y
g : _Y ⟶ _Z
⊢ (r • f) ≫ g = r • f ≫ g

Tactic:
by exact (Preadditive.rightComp X g).map_zsmul r f

Goal state after:
Module: Mathlib.CategoryTheory.Linear.Basic

Goal state before:
pp: C : Type u
inst✝¹ : Category.{v, u} C
inst✝ : Preadditive C
_X _Y Z : C
f : _X ⟶ _Y
r : ℤ
g : _Y ⟶ Z
⊢ f ≫ (r • g) = r • f ≫ g

Tactic:
exact (Preadditive.leftComp Z f).map_zsmul r g

Goal state after:
Module: Mathlib.CategoryTheory.FinCategory.Basic

Goal state before:
pp: α : Type u_1
X Y : Discrete α
⊢ Fintype (X ⟶ Y)

Tactic:
apply ULift.fintype

Goal state after:
Module: Mathlib.CategoryTheory.Limits.Shapes.Biproducts

Goal state before:
pp: J : Type w
C : Type uC
inst✝¹ : Category.{uC', uC} C
inst✝ : HasZeroMorphisms C
f : J → C
t : Bicone f
ht : IsLimit t.toCone
j : J
j' : Discrete J
⊢ t.ι j ≫ t.toCone.π.app j' = (Fan.mk (f j) fun j' ↦ if h : j = j' then eqToHom ⋯ else 0).π.app j'

Tactic:
simp [t.ι_π]

Goal state after:
Module: Mathlib.CategoryTheory.Limits.Shapes.Biproducts

Goal state before:
pp: J : Type w
C : Type uC
inst✝¹ : Category.{uC', uC} C
inst✝ : HasZeroMorphisms C
f : J → C
t : Bicone f
ht : IsColimit t.toCocone
j : J
j' : Discrete J
⊢ t.toCocone.ι.app j' ≫ t.π j = (Cofan.mk (f j) fun j' ↦ if h : j' = j then eqToHom ⋯ else 0).ι.app j'

Tactic:
simp [t.ι_π]

Goal state after:
Module: Mathlib.Algebra.Category.ModuleCat.Basic

Goal state before:
pp: R : Type u
inst✝ : Ring R
M : ModuleCat R
h : IsZero M
x : ↑M
⊢ x = 0

Tactic:
← LinearMap.id_apply (R := R) x,

Goal state after:
R : Type u
inst✝ : Ring R
M : ModuleCat R
h : IsZero M
x : ↑M
⊢ LinearMap.id x = 0
Module: Mathlib.CategoryTheory.Preadditive.Biproducts

Goal state before:
pp: C : Type u
inst✝² : Category.{v, u} C
inst✝¹ : Preadditive C
X✝ Y✝ : C
inst✝ : HasBinaryBiproduct X✝ Y✝
X Y : C
b : BinaryBicone X Y
hb : IsLimit b.fstKernelFork
T : C
f : T ⟶ X
g : T ⟶ Y
m : T ⟶ b.toCone.pt
h₁ : m ≫ BinaryFan.fst b.toCone = f
h₂ : m ≫ BinaryFan.snd b.toCone = g
⊢ m = f ≫ b.inl + g ≫ b.inr

Tactic:
by
      dsimp at m
      have h₁' : (m - (f ≫ b.inl + g ≫ b.inr)) ≫ b.fst = 0 := by simpa using sub_eq_zero.2 h₁
      have h₂' : (m - (f ≫ b.inl + g ≫ b.inr)) ≫ b.snd = 0 := by simpa using sub_eq_zero.2 h₂
      obtain ⟨q : T ⟶ Y, hq : q ≫ b.inr = m - (f ≫ b.inl + g ≫ b.inr)⟩ :=
        KernelFork.IsLimit.lift' hb _ h₁'
      rw [← sub_eq_zero, ← hq, ← Category.comp_id q, ← b.inr_snd, ← Category.assoc, hq, h₂',
        zero_comp]

Goal state after:
Module: Mathlib.Algebra.Order.Antidiag.Pi

Goal state before:
pp: ι : Type u_1
μ : Type u_2
μ' : Type u_3
inst✝³ : DecidableEq ι
inst✝² : AddCommMonoid μ
inst✝¹ : HasAntidiagonal μ
inst✝ : DecidableEq μ
n✝ : μ
d✝ : ℕ
n : μ
d : ℕ
i : μ × μ
a✝ : i ∈ ↑(antidiagonal n)
⊢ ∀ ⦃y : μ × μ⦄,
    y ∈ ↑(antidiagonal n) → i ≠ y → (Disjoint on fun ab ↦ map { toFun := Fin.cons ab.1, inj' := ⋯ } ↑(aux d ab.2)) i y

Tactic:
j

Goal state after:
ι : Type u_1
μ : Type u_2
μ' : Type u_3
inst✝³ : DecidableEq ι
inst✝² : AddCommMonoid μ
inst✝¹ : HasAntidiagonal μ
inst✝ : DecidableEq μ
n✝ : μ
d✝ : ℕ
n : μ
d : ℕ
i : μ × μ
a✝ : i ∈ ↑(antidiagonal n)
j : μ × μ
⊢ j ∈ ↑(antidiagonal n) → i ≠ j → (Disjoint on fun ab ↦ map { toFun := Fin.cons ab.1, inj' := ⋯ } ↑(aux d ab.2)) i j
Module: Mathlib.Algebra.Order.Antidiag.Pi

Goal state before:
pp: case a.mpr
ι : Type u_1
μ : Type u_2
inst✝³ : DecidableEq ι
inst✝² : AddCommMonoid μ
inst✝¹ : HasAntidiagonal μ
inst✝ : DecidableEq μ
s : Finset ι
n : μ
f : ι → μ
e : ↥s ≃ Fin #s
⊢ (s.sum f = n ∧ ∀ (i : ι), f i ≠ 0 → i ∈ s) → ∃ a, ∑ i, a i = n ∧ (fun i ↦ if hi : i ∈ s then a (e ⟨i, hi⟩) else 0) = f

Tactic:
rintro ⟨rfl, hf⟩

Goal state after:
case a.mpr
ι : Type u_1
μ : Type u_2
inst✝³ : DecidableEq ι
inst✝² : AddCommMonoid μ
inst✝¹ : HasAntidiagonal μ
inst✝ : DecidableEq μ
s : Finset ι
f : ι → μ
e : ↥s ≃ Fin #s
hf : ∀ (i : ι), f i ≠ 0 → i ∈ s
⊢ ∃ a, ∑ i, a i = s.sum f ∧ (fun i ↦ if hi : i ∈ s then a (e ⟨i, hi⟩) else 0) = f
Module: Mathlib.Algebra.Order.Antidiag.Pi

Goal state before:
pp: case mpr
ι : Type u_1
inst✝ : DecidableEq ι
s : Finset ι
n : ℕ
f : ι → ℕ
⊢ (s.sum f = n ∧ ∀ (i : ι), ¬f i = 0 → i ∈ s) →
    ∃ s_1, (∀ a ∈ s_1, a ∈ s) ∧ s_1.card = n ∧ ∀ (x : ι), Multiset.count x s_1 = f x

Tactic:
rintro ⟨rfl, hf⟩

Goal state after:
case mpr
ι : Type u_1
inst✝ : DecidableEq ι
s : Finset ι
f : ι → ℕ
hf : ∀ (i : ι), ¬f i = 0 → i ∈ s
⊢ ∃ s_1, (∀ a ∈ s_1, a ∈ s) ∧ s_1.card = s.sum f ∧ ∀ (x : ι), Multiset.count x s_1 = f x
Module: Mathlib.Combinatorics.Enumerative.Composition

Goal state before:
pp: case mpr
c : Composition 0
⊢ c.blocks.length ≤ 0

Tactic:
exact c.length_le

Goal state after:
Module: Mathlib.CategoryTheory.Preadditive.Biproducts

Goal state before:
pp: case intro
C : Type u
inst✝⁵ : Category.{v, u} C
inst✝⁴ : Preadditive C
σ τ : Type
inst✝³ : Finite τ
S : σ → C
inst✝² : HasBiproduct S
T : τ → C
inst✝¹ : HasBiproduct T
s : σ
f : ⨁ S ⟶ ⨁ T
inst✝ : IsIso f
val✝ : Fintype τ
z : ∀ (t : τ), biproduct.ι S s ≫ f ≫ biproduct.π T t = 0
reassoced : ∀ {t : τ} {W : C} (h : T t ⟶ W), biproduct.ι S s ≫ f ≫ biproduct.π T t ≫ h = 0 ≫ h
x : S s ⟶ S s := biproduct.ι S s ≫ f ≫ inv f ≫ biproduct.π S s
h₁ : x = 𝟙 (S s)
h₀ : x = 0
⊢ 𝟙 (S s) = 0

Tactic:
exact h₁.symm.trans h₀

Goal state after:
Module: Mathlib.CategoryTheory.Preadditive.Biproducts

Goal state before:
pp: C : Type u
inst✝⁵ : Category.{v, u} C
inst✝⁴ : Preadditive C
σ τ : Type
inst✝³ : Fintype τ
S : σ → C
inst✝² : HasBiproduct S
T : τ → C
inst✝¹ : HasBiproduct T
s : σ
nz : 𝟙 (S s) ≠ 0
f : ⨁ S ⟶ ⨁ T
inst✝ : IsIso f
⊢ Trunc ((t : τ) ×' biproduct.ι S s ≫ f ≫ biproduct.π T t ≠ 0)

Tactic:
apply truncSigmaOfExists

Goal state after:
C : Type u
inst✝⁵ : Category.{v, u} C
inst✝⁴ : Preadditive C
σ τ : Type
inst✝³ : Fintype τ
S : σ → C
inst✝² : HasBiproduct S
T : τ → C
inst✝¹ : HasBiproduct T
s : σ
nz : 𝟙 (S s) ≠ 0
f : ⨁ S ⟶ ⨁ T
inst✝ : IsIso f
⊢ ∃ a, biproduct.ι S s ≫ f ≫ biproduct.π T a ≠ 0
Module: Mathlib.Combinatorics.Enumerative.Composition

Goal state before:
pp: c c' : (n : ℕ) × Composition n
⊢ c = c' ↔ c.snd.blocks = c'.snd.blocks

Tactic:
by
  refine ⟨fun H => by rw [H], fun H => ?_⟩
  rcases c with ⟨n, c⟩
  rcases c' with ⟨n', c'⟩
  have : n = n' := by rw [← c.blocks_sum, ← c'.blocks_sum, H]
  induction this
  congr
  ext1
  exact H

Goal state after:
Module: Mathlib.Combinatorics.Enumerative.Composition

Goal state before:

Tactic:
∑ k, c.blocksFun k ≤ c.blocksFun i := by simp only [c.sum_blocksFun, hi]
        _ < ∑ k, c.blocksFun k :=
          Finset.single_lt_sum ji (Finset.mem_univ _) (Finset.mem_univ _) (c.one_le_blocksFun j)
            fun _ _ _ => zero_le

Goal state after:
Module: Mathlib.Logic.Equiv.Fintype

Goal state before:
pp: α : Type u_1
p q : α → Prop
inst✝² : DecidablePred p
inst✝¹ : DecidablePred q
inst✝ : Finite ↑{x | p x}
e : { x // p x } ≃ { x // q x }
x : α
hx : ¬p x
⊢ e.extendSubtype x = ↑(e.toCompl ⟨x, hx⟩)

Tactic:
simp only [extendSubtype, subtypeCongr, Equiv.trans_apply,
    sumCompl_symm_apply_of_neg hx]
  rfl

Goal state after:
Module: Mathlib.GroupTheory.Perm.Support

Goal state before:
pp: case insert
α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
ι : Type u_2
k : ι → Perm α
i : ι
s : Finset ι
hi : i ∉ s
hrec :
  ∀ (hs : (↑s).Pairwise fun i j ↦ (k i).Disjoint (k j)), (s.noncommProd k ⋯).support = s.biUnion fun i ↦ (k i).support
hs : (↑(insert i s)).Pairwise fun i j ↦ (k i).Disjoint (k j)
hs' : (↑s).Pairwise fun i j ↦ (k i).Disjoint (k j)
⊢ (k i).support ∪ (s.noncommProd k ⋯).support = (k i).support ∪ s.biUnion fun i ↦ (k i).support

pp: case insert
α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
ι : Type u_2
k : ι → Perm α
i : ι
s : Finset ι
hi : i ∉ s
hrec :
  ∀ (hs : (↑s).Pairwise fun i j ↦ (k i).Disjoint (k j)), (s.noncommProd k ⋯).support = s.biUnion fun i ↦ (k i).support
hs : (↑(insert i s)).Pairwise fun i j ↦ (k i).Disjoint (k j)
hs' : (↑s).Pairwise fun i j ↦ (k i).Disjoint (k j)
⊢ (k i).Disjoint (s.noncommProd k ⋯)

Tactic:
hrec hs'

Goal state after:
case insert
α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
ι : Type u_2
k : ι → Perm α
i : ι
s : Finset ι
hi : i ∉ s
hrec :
  ∀ (hs : (↑s).Pairwise fun i j ↦ (k i).Disjoint (k j)), (s.noncommProd k ⋯).support = s.biUnion fun i ↦ (k i).support
hs : (↑(insert i s)).Pairwise fun i j ↦ (k i).Disjoint (k j)
hs' : (↑s).Pairwise fun i j ↦ (k i).Disjoint (k j)
⊢ ((k i).support ∪ s.biUnion fun i ↦ (k i).support) = (k i).support ∪ s.biUnion fun i ↦ (k i).support

case insert
α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
ι : Type u_2
k : ι → Perm α
i : ι
s : Finset ι
hi : i ∉ s
hrec :
  ∀ (hs : (↑s).Pairwise fun i j ↦ (k i).Disjoint (k j)), (s.noncommProd k ⋯).support = s.biUnion fun i ↦ (k i).support
hs : (↑(insert i s)).Pairwise fun i j ↦ (k i).Disjoint (k j)
hs' : (↑s).Pairwise fun i j ↦ (k i).Disjoint (k j)
⊢ (k i).Disjoint (s.noncommProd k ⋯)
Module: Mathlib.GroupTheory.Perm.List

Goal state before:
pp: case cons.cons
α : Type u_1
inst✝ : DecidableEq α
x y : α
tl : List α
h : (x :: y :: tl).Nodup
hl : 1 < (x :: y :: tl).length
⊢ y = (x :: y :: tl)[1]

Tactic:
getElem_cons_succ,

Goal state after:
case cons.cons
α : Type u_1
inst✝ : DecidableEq α
x y : α
tl : List α
h : (x :: y :: tl).Nodup
hl : 1 < (x :: y :: tl).length
⊢ y = (y :: tl)[0]
Module: Mathlib.GroupTheory.Perm.Support

Goal state before:
pp: α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
f : Perm α
⊢ #f.support ≤ 0 ∨ #f.support = 1 ↔ f = 1

Tactic:
Nat.le_zero,

Goal state after:
α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
f : Perm α
⊢ #f.support = 0 ∨ #f.support = 1 ↔ f = 1
Module: Mathlib.Data.Fintype.Perm

Goal state before:
pp: case refine_3
α : Type u_1
inst✝ : DecidableEq α
a : α
l : List α
hl : (a :: l).Nodup
hl' : l.Nodup
hln' : (permsOfList l).Nodup
hmeml : ∀ {f : Equiv.Perm α}, f ∈ permsOfList l → f a = a
i : ℕ
⊢ ∀ (j : ℕ) (_hi : i < l.length) (_hj : j < l.length),
    i < j → (List.Disjoint on fun b ↦ List.map (fun f ↦ Equiv.swap a b * f) (permsOfList l)) l[i] l[j]

Tactic:
j

Goal state after:
case refine_3
α : Type u_1
inst✝ : DecidableEq α
a : α
l : List α
hl : (a :: l).Nodup
hl' : l.Nodup
hln' : (permsOfList l).Nodup
hmeml : ∀ {f : Equiv.Perm α}, f ∈ permsOfList l → f a = a
i j : ℕ
⊢ ∀ (_hi : i < l.length) (_hj : j < l.length),
    i < j → (List.Disjoint on fun b ↦ List.map (fun f ↦ Equiv.swap a b * f) (permsOfList l)) l[i] l[j]
Module: Mathlib.GroupTheory.Perm.Sign

Goal state before:
pp: n : ℕ
f : Perm (Fin n)
x✝ : (_ : Fin n) × Fin n
a₁ a₂ : Fin n
ha : ⟨a₁, a₂⟩ ∈ finPairsLT n
⊢ f.signBijAux ⟨a₁, a₂⟩ ∈ finPairsLT n

Tactic:
by
    unfold signBijAux
    split_ifs with h
    · exact mem_finPairsLT.2 h
    · exact mem_finPairsLT.2
        ((le_of_not_gt h).lt_of_ne fun h => (mem_finPairsLT.1 ha).ne (f.injective h.symm))

Goal state after: