mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.LinearAlgebra.SesquilinearForm.Basic

Goal state before:
pp: case inr.inr
R : Type u_1
M : Type u_5
inst✝⁴ : CommRing R
inst✝³ : LinearOrder R
inst✝² : IsStrictOrderedRing R
inst✝¹ : AddCommGroup M
inst✝ : Module R M
B : LinearMap.BilinForm R M
hs : ∀ (x : M), 0 ≤ (B x) x
x y : M
aux : ∀ (x y : M), 0 ≤ (B x) x * ((B x) x * (B y) y - (B x) y * (B y) x)
hx : (B x) x = 0
hy : (B y) y ≤ 0
⊢ (B x) y * (B y) x ≤ (B x) x * (B y) y

Tactic:
· replace hy : B y y = 0 := le_antisymm hy (hs y)
      suffices B x y = - B y x by simpa [this, hx, hy] using mul_self_nonneg (B y x)
      rw [eq_neg_iff_add_eq_zero]
      apply le_antisymm
      · simpa [hx, hy, le_neg_iff_add_nonpos_left] using hs (x - y)
      · simpa [hx, hy] using hs (x + y)

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

Goal state before:
pp: R : Type u
inst✝ : Ring R
M N P : ModuleCat R
f✝ f : M ⟶ N
g : N ⟶ P
H : Function.Exact ⇑(Hom.hom f) ⇑(Hom.hom g)
H₂ : Function.Injective ⇑(Hom.hom f)
⊢ f ≫ g = 0

Tactic:
ext; exact H.apply_apply_eq_zero _

Goal state after:
Module: Mathlib.Algebra.Category.FGModuleCat.Limits

Goal state before:
pp: J✝ : Type
inst✝⁴ : SmallCategory J✝
inst✝³ : FinCategory J✝
k : Type u
inst✝² : Ring k
J : Type
inst✝¹ : Finite J
Z : J → ModuleCat k
inst✝ : ∀ (j : J), Module.Finite k ↑(Z j)
⊢ Module.Finite k ↑(ModuleCat.of k ((j : J) → ↑(Z j)))

Tactic:
by unfold ModuleCat.of; infer_instance

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

Goal state before:
pp: R : Type u
inst✝ : Ring R
M N P : ModuleCat R
f✝ f : M ⟶ N
g : N ⟶ P
H : Function.Exact ⇑(Hom.hom f) ⇑(Hom.hom g)
H₂ : Function.Surjective ⇑(Hom.hom g)
⊢ f ≫ g = 0

Tactic:
ext; exact H.apply_apply_eq_zero _

Goal state after:
Module: Mathlib.LinearAlgebra.Dual.Lemmas

Goal state before:
pp: K : Type u_1
V₁ : Type u_2
inst✝³ : DivisionRing K
inst✝² : AddCommGroup V₁
inst✝¹ : Module K V₁
inst✝ : FiniteDimensional K V₁
f g : Dual K V₁
x : V₁
h : LinearMap.ker f = LinearMap.ker g
h' : f x = g x
hx : f x ≠ 0
p : Submodule K V₁ := K ∙ x
hp : p ≠ ⊥
hpf : Disjoint (LinearMap.ker f) p
hf : f ≠ 0
y : V₁
hy : y ∈ LinearMap.ker f
z : V₁
hz : z ∈ p
hy' : g y = 0
⊢ f (y + z) = g (y + z)

Tactic:
replace hy : f y = 0 := by rwa [LinearMap.mem_ker] at hy

Goal state after:
K : Type u_1
V₁ : Type u_2
inst✝³ : DivisionRing K
inst✝² : AddCommGroup V₁
inst✝¹ : Module K V₁
inst✝ : FiniteDimensional K V₁
f g : Dual K V₁
x : V₁
h : LinearMap.ker f = LinearMap.ker g
h' : f x = g x
hx : f x ≠ 0
p : Submodule K V₁ := K ∙ x
hp : p ≠ ⊥
hpf : Disjoint (LinearMap.ker f) p
hf : f ≠ 0
y z : V₁
hz : z ∈ p
hy' : g y = 0
hy : f y = 0
⊢ f (y + z) = g (y + z)
Module: Mathlib.CategoryTheory.Limits.Preserves.Shapes.Kernels

Goal state before:
pp: C : Type u₁
inst✝⁷ : Category.{v₁, u₁} C
inst✝⁶ : HasZeroMorphisms C
D : Type u₂
inst✝⁵ : Category.{v₂, u₂} D
inst✝⁴ : HasZeroMorphisms D
G : C ⥤ D
inst✝³ : G.PreservesZeroMorphisms
X Y Z : C
f : X ⟶ Y
h : Z ⟶ X
w : h ≫ f = 0
inst✝² : HasKernel f
inst✝¹ : HasKernel (G.map f)
inst✝ : PreservesLimit (parallelPair f 0) G
⊢ IsIso (kernelComparison f G)

Tactic:
by
  rw [← PreservesKernel.iso_hom]
  infer_instance

Goal state after:
Module: Mathlib.CategoryTheory.Abelian.NonPreadditive

Goal state before:
pp: C : Type u
inst✝¹ : Category.{v, u} C
inst✝ : NonPreadditiveAbelian C
P Q : C
f : P ⟶ Q
I : C := Abelian.coimage f
i : Abelian.coimage f ⟶ Q := Abelian.factorThruCoimage f
p : P ⟶ cokernel (kernel.ι f) := cokernel.π (kernel.ι f)
R : C
g : R ⟶ I
hgi : g ≫ i = 0
u : P ⟶ cokernel g := p ≫ cokernel.π g
hu : NormalEpi u
h : NormalEpi.W u ⟶ P := NormalEpi.g
t : cokernel g ⟶ Q
ht : cokernel.π g ≫ t = i
hf : h ≫ f = 0
l : NormalEpi.W u ⟶ kernel f
hl : l ≫ kernel.ι f = h
⊢ g = 0

Tactic:
have hhp : h ≫ p = 0 :=
      calc
        h ≫ p = (l ≫ kernel.ι f) ≫ p := hl ▸ rfl
        _ = l ≫ 0 := by rw [Category.assoc, cokernel.condition]
        _ = 0 := comp_zero

Goal state after:
C : Type u
inst✝¹ : Category.{v, u} C
inst✝ : NonPreadditiveAbelian C
P Q : C
f : P ⟶ Q
I : C := Abelian.coimage f
i : Abelian.coimage f ⟶ Q := Abelian.factorThruCoimage f
p : P ⟶ cokernel (kernel.ι f) := cokernel.π (kernel.ι f)
R : C
g : R ⟶ I
hgi : g ≫ i = 0
u : P ⟶ cokernel g := p ≫ cokernel.π g
hu : NormalEpi u
h : NormalEpi.W u ⟶ P := NormalEpi.g
t : cokernel g ⟶ Q
ht : cokernel.π g ≫ t = i
hf : h ≫ f = 0
l : NormalEpi.W u ⟶ kernel f
hl : l ≫ kernel.ι f = h
hhp : h ≫ p = 0
⊢ g = 0
Module: Mathlib.CategoryTheory.Abelian.NonPreadditive

Goal state before:
pp: C : Type u
inst✝¹ : Category.{v, u} C
inst✝ : NonPreadditiveAbelian C
A : C
hl : IsLimit (KernelFork.ofι (diag A) ⋯) :=
  monoIsKernelOfCokernel (colimit.cocone (parallelPair (diag A) 0)) (colimit.isColimit (parallelPair (diag A) 0))
Z : C
x : Z ⟶ A
hx : x ≫ r A = 0
hxx : (x ≫ prod.lift (𝟙 A) 0) ≫ cokernel.π (diag A) = 0
y : Z ⟶ (KernelFork.ofι (diag A) ⋯).pt
hy : y ≫ diag A = x ≫ prod.lift (𝟙 A) 0
hyy : y = 0
⊢ x = 0

Tactic:
have : Mono (prod.lift (𝟙 A) (0 : A ⟶ A)) := mono_of_mono_fac (prod.lift_fst _ _)

Goal state after:
C : Type u
inst✝¹ : Category.{v, u} C
inst✝ : NonPreadditiveAbelian C
A : C
hl : IsLimit (KernelFork.ofι (diag A) ⋯) :=
  monoIsKernelOfCokernel (colimit.cocone (parallelPair (diag A) 0)) (colimit.isColimit (parallelPair (diag A) 0))
Z : C
x : Z ⟶ A
hx : x ≫ r A = 0
hxx : (x ≫ prod.lift (𝟙 A) 0) ≫ cokernel.π (diag A) = 0
y : Z ⟶ (KernelFork.ofι (diag A) ⋯).pt
hy : y ≫ diag A = x ≫ prod.lift (𝟙 A) 0
hyy : y = 0
this : Mono (prod.lift (𝟙 A) 0)
⊢ x = 0
Module: Mathlib.CategoryTheory.Limits.Shapes.NormalMono.Equalizers

Goal state before:
pp: C : Type u_1
inst✝⁶ : Category.{v_1, u_1} C
inst✝⁵ : HasZeroMorphisms C
inst✝⁴ : HasFiniteCoproducts C
inst✝³ : HasCokernels C
inst✝² : IsNormalEpiCategory C
X Y Z : C
a : X ⟶ Y
b : X ⟶ Z
inst✝¹ : Epi a
inst✝ : Epi b
P : C
f : P ⟶ X
hfa : f ≫ a = 0
i : IsColimit (CokernelCofork.ofπ a hfa)
Q : C
g : Q ⟶ X
hgb : g ≫ b = 0
i' : IsColimit (CokernelCofork.ofπ b hgb)
a' : (CokernelCofork.ofπ a hfa).pt ⟶ cokernel (coprod.desc f g)
ha' : Cofork.π (CokernelCofork.ofπ a hfa) ≫ a' = cokernel.π (coprod.desc f g)
b' : (CokernelCofork.ofπ b hgb).pt ⟶ cokernel (coprod.desc f g)
hb' : Cofork.π (CokernelCofork.ofπ b hgb) ≫ b' = cokernel.π (coprod.desc f g)
s : PushoutCocone a b
⊢ f ≫ b ≫ s.inr = f ≫ a ≫ s.inl

Tactic:
rw [PushoutCocone.condition]

Goal state after:
Module: Mathlib.CategoryTheory.Abelian.NonPreadditive

Goal state before:
pp: case refine_2
C : Type u
inst✝¹ : Category.{v, u} C
inst✝ : NonPreadditiveAbelian C
A : C
hlp : prod.lift (𝟙 A) 0 ≫ prod.snd = 0
s : Fork prod.snd 0
m : s.pt ⟶ (KernelFork.ofι (prod.lift (𝟙 A) 0) hlp).pt
h : m ≫ Fork.ι (KernelFork.ofι (prod.lift (𝟙 A) 0) hlp) = s.ι
⊢ m = s.ι ≫ prod.fst

Tactic:
have : Mono (prod.lift (𝟙 A) (0 : A ⟶ A)) := mono_of_mono_fac (prod.lift_fst _ _)

Goal state after:
case refine_2
C : Type u
inst✝¹ : Category.{v, u} C
inst✝ : NonPreadditiveAbelian C
A : C
hlp : prod.lift (𝟙 A) 0 ≫ prod.snd = 0
s : Fork prod.snd 0
m : s.pt ⟶ (KernelFork.ofι (prod.lift (𝟙 A) 0) hlp).pt
h : m ≫ Fork.ι (KernelFork.ofι (prod.lift (𝟙 A) 0) hlp) = s.ι
this : Mono (prod.lift (𝟙 A) 0)
⊢ m = s.ι ≫ prod.fst
Module: Mathlib.CategoryTheory.Abelian.Basic

Goal state before:
pp: C : Type u
inst✝³ : Category.{v, u} C
inst✝² : Preadditive C
inst✝¹ : HasKernels C
inst✝ : HasCokernels C
X Y : C
f : X ⟶ Y
⊢ (imageMonoFactorisation f).e = cokernel.π (kernel.ι f) ≫ coimageImageComparison f

Tactic:
by
  dsimp
  ext
  simp only [Abelian.coimageImageComparison, Category.assoc,
    cokernel.π_desc_assoc]

Goal state after:
Module: Mathlib.CategoryTheory.Abelian.NonPreadditive

Goal state before:
pp: C : Type u
inst✝¹ : Category.{v, u} C
inst✝ : NonPreadditiveAbelian C
X Y Z : C
f g : X ⟶ Y
h : Y ⟶ Z
⊢ (f + g) ≫ h = f ≫ h + g ≫ h

Tactic:
rw [add_def, sub_comp, neg_def, sub_comp, zero_comp, add_def, neg_def]

Goal state after:
Module: Mathlib.Algebra.Homology.ShortComplex.Homology

Goal state before:
pp: C : Type u
inst✝¹ : Category.{v, u} C
inst✝ : HasZeroMorphisms C
S S₁ S₂ S₃ S₄ : ShortComplex C
φ : S₁ ⟶ S₂
h₁ : S₁.HomologyData
h₂ : S₂.HomologyData
left₁ : LeftHomologyMapData φ h₁.left h₂.left
right₁ : RightHomologyMapData φ h₁.right h₂.right
left₂ : LeftHomologyMapData φ h₁.left h₂.left
right₂ : RightHomologyMapData φ h₁.right h₂.right
⊢ { left := left₁, right := right₁ } = { left := left₂, right := right₂ }

Tactic:
simp only [mk.injEq, eq_iff_true_of_subsingleton, and_self]

Goal state after:
Module: Mathlib.Algebra.Homology.ShortComplex.RightHomology

Goal state before:
pp: C : Type u_1
inst✝¹ : Category.{v_1, u_1} C
inst✝ : HasZeroMorphisms C
S S₁ S₂ S₃ : ShortComplex C
φ : S₁ ⟶ S₂
h₁ : S₁.RightHomologyData
h₂ : S₂.RightHomologyData
ψ₁ ψ₂ : RightHomologyMapData φ h₁ h₂
⊢ h₁.p ≫ ψ₁.φQ = h₁.p ≫ ψ₂.φQ

Tactic:
commp,

Goal state after:
C : Type u_1
inst✝¹ : Category.{v_1, u_1} C
inst✝ : HasZeroMorphisms C
S S₁ S₂ S₃ : ShortComplex C
φ : S₁ ⟶ S₂
h₁ : S₁.RightHomologyData
h₂ : S₂.RightHomologyData
ψ₁ ψ₂ : RightHomologyMapData φ h₁ h₂
⊢ φ.τ₂ ≫ h₂.p = h₁.p ≫ ψ₂.φQ
Module: Mathlib.Algebra.Homology.ShortComplex.RightHomology

Goal state before:
pp: C : Type u_1
inst✝² : Category.{v_1, u_1} C
inst✝¹ : HasZeroMorphisms C
S S₁ S₂ S₃ : ShortComplex C
inst✝ : S.HasRightHomology
hg : S.g = 0
this : IsIso S.rightHomologyι
⊢ S.opcycles ≅ S.rightHomology

Tactic:
exact (asIso S.rightHomologyι).symm

Goal state after:
Module: Mathlib.Algebra.Homology.ShortComplex.LeftHomology

Goal state before:
pp: C : Type u_1
inst✝⁴ : Category.{v_1, u_1} C
inst✝³ : HasZeroMorphisms C
S₁ S₂ : ShortComplex C
φ : S₁ ⟶ S₂
h : S₂.LeftHomologyData
inst✝² : Epi φ.τ₁
inst✝¹ : IsIso φ.τ₂
inst✝ : Mono φ.τ₃
⊢ (ofEpiOfIsIsoOfMono' φ h).f' = φ.τ₁ ≫ h.f'

Tactic:
← cancel_mono (ofEpiOfIsIsoOfMono' φ h).i,

Goal state after:
C : Type u_1
inst✝⁴ : Category.{v_1, u_1} C
inst✝³ : HasZeroMorphisms C
S₁ S₂ : ShortComplex C
φ : S₁ ⟶ S₂
h : S₂.LeftHomologyData
inst✝² : Epi φ.τ₁
inst✝¹ : IsIso φ.τ₂
inst✝ : Mono φ.τ₃
⊢ (ofEpiOfIsIsoOfMono' φ h).f' ≫ (ofEpiOfIsIsoOfMono' φ h).i = (φ.τ₁ ≫ h.f') ≫ (ofEpiOfIsIsoOfMono' φ h).i
Module: Mathlib.Algebra.Homology.ShortComplex.RightHomology

Goal state before:
pp: C : Type u_1
inst✝⁴ : Category.{v_1, u_1} C
inst✝³ : HasZeroMorphisms C
S S₁ S₂ S₃ : ShortComplex C
φ : S₁ ⟶ S₂
h₁ : S₁.RightHomologyData
h₂ : S₂.RightHomologyData
inst✝² : Epi φ.τ₁
inst✝¹ : IsIso φ.τ₂
inst✝ : Mono φ.τ₃
h₂' : S₂.RightHomologyData := RightHomologyData.ofEpiOfIsIsoOfMono φ h₁
⊢ IsIso (rightHomologyMap' φ h₁ h₂')

Tactic:
(RightHomologyMapData.ofEpiOfIsIsoOfMono φ h₁).rightHomologyMap'_eq

Goal state after:
C : Type u_1
inst✝⁴ : Category.{v_1, u_1} C
inst✝³ : HasZeroMorphisms C
S S₁ S₂ S₃ : ShortComplex C
φ : S₁ ⟶ S₂
h₁ : S₁.RightHomologyData
h₂ : S₂.RightHomologyData
inst✝² : Epi φ.τ₁
inst✝¹ : IsIso φ.τ₂
inst✝ : Mono φ.τ₃
h₂' : S₂.RightHomologyData := RightHomologyData.ofEpiOfIsIsoOfMono φ h₁
⊢ IsIso (RightHomologyMapData.ofEpiOfIsIsoOfMono φ h₁).φH
Module: Mathlib.Algebra.Homology.ShortComplex.Homology

Goal state before:
pp: C : Type u
inst✝² : Category.{v, u} C
inst✝¹ : HasZeroMorphisms C
S : ShortComplex C
hf : S.f = 0
inst✝ : S.HasHomology
⊢ IsIso S.homologyπ

Tactic:
have := S.isIso_leftHomologyπ hf
  dsimp only [homologyπ]
  infer_instance

Goal state after:
Module: Mathlib.Algebra.Homology.ShortComplex.Homology

Goal state before:
pp: C : Type u
inst✝³ : Category.{v, u} C
inst✝² : HasZeroMorphisms C
S₁ S₂ : ShortComplex C
φ : S₁ ⟶ S₂
inst✝¹ : S₁.HasHomology
inst✝ : S₂.HasHomology
h : Epi (cyclesMap φ)
⊢ Epi (homologyMap φ)

Tactic:
have : Epi (S₁.homologyπ ≫ homologyMap φ) := by
    rw [homologyπ_naturality φ]
    apply epi_comp

Goal state after:
C : Type u
inst✝³ : Category.{v, u} C
inst✝² : HasZeroMorphisms C
S₁ S₂ : ShortComplex C
φ : S₁ ⟶ S₂
inst✝¹ : S₁.HasHomology
inst✝ : S₂.HasHomology
h : Epi (cyclesMap φ)
this : Epi (S₁.homologyπ ≫ homologyMap φ)
⊢ Epi (homologyMap φ)
Module: Mathlib.Algebra.Homology.ShortComplex.PreservesHomology

Goal state before:
pp: C : Type u_1
D : Type u_2
inst✝⁶ : Category.{v_1, u_1} C
inst✝⁵ : Category.{v_2, u_2} D
inst✝⁴ : HasZeroMorphisms C
inst✝³ : HasZeroMorphisms D
S₁ S₂ : ShortComplex C
φ : S₁ ⟶ S₂
hr₁ : S₁.RightHomologyData
hr₂ : S₂.RightHomologyData
F : C ⥤ D
inst✝² : F.PreservesZeroMorphisms
inst✝¹ : hr₁.IsPreservedBy F
inst✝ : hr₂.IsPreservedBy F
γ : RightHomologyMapData φ hr₁ hr₂
⊢ F.map γ.φH = (γ.map F).φH

Tactic:
ShortComplex.RightHomologyMapData.map_φH

Goal state after:
C : Type u_1
D : Type u_2
inst✝⁶ : Category.{v_1, u_1} C
inst✝⁵ : Category.{v_2, u_2} D
inst✝⁴ : HasZeroMorphisms C
inst✝³ : HasZeroMorphisms D
S₁ S₂ : ShortComplex C
φ : S₁ ⟶ S₂
hr₁ : S₁.RightHomologyData
hr₂ : S₂.RightHomologyData
F : C ⥤ D
inst✝² : F.PreservesZeroMorphisms
inst✝¹ : hr₁.IsPreservedBy F
inst✝ : hr₂.IsPreservedBy F
γ : RightHomologyMapData φ hr₁ hr₂
⊢ F.map γ.φH = F.map γ.φH
Module: Mathlib.Algebra.Homology.ShortComplex.Limits

Goal state before:
pp: J : Type u_1
C : Type u_2
inst✝² : Category.{v_1, u_1} J
inst✝¹ : Category.{v_2, u_2} C
inst✝ : HasZeroMorphisms C
F : J ⥤ ShortComplex C
c : Cocone F
h₁ : IsColimit (π₁.mapCocone c)
h₂ : IsColimit (π₂.mapCocone c)
h₃ : IsColimit (π₃.mapCocone c)
s : Cocone F
j : J
⊢ (π₂.mapCocone c).ι.app j ≫ h₂.desc (π₂.mapCocone s) ≫ s.pt.g =
    (π₂.mapCocone c).ι.app j ≫ c.pt.g ≫ h₃.desc (π₃.mapCocone s)

Tactic:
have eq₂ := h₂.fac (π₂.mapCocone s)
        have eq₃ := h₃.fac (π₃.mapCocone s)
        have eq₂₃ := fun j => (c.ι.app j).comm₂₃
        have eq₂₃' := fun j => (s.ι.app j).comm₂₃
        dsimp at eq₂ eq₃ eq₂₃ eq₂₃' ⊢
        rw [reassoc_of% (eq₂ j), eq₂₃', reassoc_of% eq₂₃, eq₃]

Goal state after:
Module: Mathlib.Algebra.Homology.ShortComplex.Abelian

Goal state before:
pp: C : Type u
inst✝¹ : Category.{v, u} C
inst✝ : Abelian C
S : ShortComplex C
kf : KernelFork S.g
hkf : IsLimit kf
⊢ hkf.lift (KernelFork.ofι S.f ⋯) = S.toCycles ≫ (S.isoCyclesOfIsLimit hkf).inv

Tactic:
have := Fork.IsLimit.mono hkf

Goal state after:
C : Type u
inst✝¹ : Category.{v, u} C
inst✝ : Abelian C
S : ShortComplex C
kf : KernelFork S.g
hkf : IsLimit kf
this : Mono (Fork.ι kf)
⊢ hkf.lift (KernelFork.ofι S.f ⋯) = S.toCycles ≫ (S.isoCyclesOfIsLimit hkf).inv
Module: Mathlib.Algebra.Homology.ShortComplex.Limits

Goal state before:
pp: case h₂
J : Type u_1
C : Type u_2
inst✝⁵ : Category.{v_1, u_1} J
inst✝⁴ : Category.{v_2, u_2} C
inst✝³ : HasZeroMorphisms C
F : J ⥤ ShortComplex C
inst✝² : HasColimit (F ⋙ π₁)
inst✝¹ : HasColimit (F ⋙ π₂)
inst✝ : HasColimit (F ⋙ π₃)
x✝¹ x✝ : J
f : x✝¹ ⟶ x✝
⊢ (F.map f ≫
        { τ₁ := colimit.ι (F ⋙ π₁) x✝, τ₂ := colimit.ι (F ⋙ π₂) x✝, τ₃ := colimit.ι (F ⋙ π₃) x✝, comm₁₂ := ⋯,
          comm₂₃ := ⋯ }).τ₂ =
    ({ τ₁ := colimit.ι (F ⋙ π₁) x✝¹, τ₂ := colimit.ι (F ⋙ π₂) x✝¹, τ₃ := colimit.ι (F ⋙ π₃) x✝¹, comm₁₂ := ⋯,
          comm₂₃ := ⋯ } ≫
        ((const J).obj
              { X₁ := colimit (F ⋙ π₁), X₂ := colimit (F ⋙ π₂), X₃ := colimit (F ⋙ π₃),
                f := colimMap (F.whiskerLeft π₁Toπ₂), g := colimMap (F.whiskerLeft π₂Toπ₃), zero := ⋯ }).map
          f).τ₂

pp: case h₃
J : Type u_1
C : Type u_2
inst✝⁵ : Category.{v_1, u_1} J
inst✝⁴ : Category.{v_2, u_2} C
inst✝³ : HasZeroMorphisms C
F : J ⥤ ShortComplex C
inst✝² : HasColimit (F ⋙ π₁)
inst✝¹ : HasColimit (F ⋙ π₂)
inst✝ : HasColimit (F ⋙ π₃)
x✝¹ x✝ : J
f : x✝¹ ⟶ x✝
⊢ (F.map f ≫
        { τ₁ := colimit.ι (F ⋙ π₁) x✝, τ₂ := colimit.ι (F ⋙ π₂) x✝, τ₃ := colimit.ι (F ⋙ π₃) x✝, comm₁₂ := ⋯,
          comm₂₃ := ⋯ }).τ₃ =
    ({ τ₁ := colimit.ι (F ⋙ π₁) x✝¹, τ₂ := colimit.ι (F ⋙ π₂) x✝¹, τ₃ := colimit.ι (F ⋙ π₃) x✝¹, comm₁₂ := ⋯,
          comm₂₃ := ⋯ } ≫
        ((const J).obj
              { X₁ := colimit (F ⋙ π₁), X₂ := colimit (F ⋙ π₂), X₃ := colimit (F ⋙ π₃),
                f := colimMap (F.whiskerLeft π₁Toπ₂), g := colimMap (F.whiskerLeft π₂Toπ₃), zero := ⋯ }).map
          f).τ₃

Tactic:
· simp [← colimit.w (F ⋙ π₂) f]

Goal state after:
case h₃
J : Type u_1
C : Type u_2
inst✝⁵ : Category.{v_1, u_1} J
inst✝⁴ : Category.{v_2, u_2} C
inst✝³ : HasZeroMorphisms C
F : J ⥤ ShortComplex C
inst✝² : HasColimit (F ⋙ π₁)
inst✝¹ : HasColimit (F ⋙ π₂)
inst✝ : HasColimit (F ⋙ π₃)
x✝¹ x✝ : J
f : x✝¹ ⟶ x✝
⊢ (F.map f ≫
        { τ₁ := colimit.ι (F ⋙ π₁) x✝, τ₂ := colimit.ι (F ⋙ π₂) x✝, τ₃ := colimit.ι (F ⋙ π₃) x✝, comm₁₂ := ⋯,
          comm₂₃ := ⋯ }).τ₃ =
    ({ τ₁ := colimit.ι (F ⋙ π₁) x✝¹, τ₂ := colimit.ι (F ⋙ π₂) x✝¹, τ₃ := colimit.ι (F ⋙ π₃) x✝¹, comm₁₂ := ⋯,
          comm₂₃ := ⋯ } ≫
        ((const J).obj
              { X₁ := colimit (F ⋙ π₁), X₂ := colimit (F ⋙ π₂), X₃ := colimit (F ⋙ π₃),
                f := colimMap (F.whiskerLeft π₁Toπ₂), g := colimMap (F.whiskerLeft π₂Toπ₃), zero := ⋯ }).map
          f).τ₃
Module: Mathlib.CategoryTheory.Adjunction.Reflective

Goal state before:
pp: C : Type u₁
D : Type u₂
inst✝³ : Category.{v₁, u₁} C
inst✝² : Category.{v₂, u₂} D
j : C ⥤ D
inst✝¹ : Coreflective j
A : D
inst✝ : IsSplitEpi ((coreflectorAdjunction j).counit.app A)
ε : coreflector j ⋙ j ⟶ 𝟭 D := (coreflectorAdjunction j).counit
this : IsIso (ε.app (j.obj ((coreflector j).obj A)))
⊢ Mono (ε.app A ≫ section_ (ε.app A))

Tactic:
rw [show ε.app A ≫ section_ _ = _ from (ε.naturality (section_ (ε.app A))).symm]

Goal state after:
C : Type u₁
D : Type u₂
inst✝³ : Category.{v₁, u₁} C
inst✝² : Category.{v₂, u₂} D
j : C ⥤ D
inst✝¹ : Coreflective j
A : D
inst✝ : IsSplitEpi ((coreflectorAdjunction j).counit.app A)
ε : coreflector j ⋙ j ⟶ 𝟭 D := (coreflectorAdjunction j).counit
this : IsIso (ε.app (j.obj ((coreflector j).obj A)))
⊢ Mono ((coreflector j ⋙ j).map (section_ (ε.app A)) ≫ ε.app ((coreflector j ⋙ j).obj A))
Module: Mathlib.Algebra.Homology.ShortComplex.Exact

Goal state before:
pp: C : Type u_1
inst✝¹ : Category.{v_1, u_1} C
inst✝ : Preadditive C
S : ShortComplex C
hS : S.Exact
hg : S.g = 0
this : S.HasHomology
⊢ Epi S.f

Tactic:
have := hS.mono_fromOpcycles

Goal state after:
C : Type u_1
inst✝¹ : Category.{v_1, u_1} C
inst✝ : Preadditive C
S : ShortComplex C
hS : S.Exact
hg : S.g = 0
this✝ : S.HasHomology
this : Mono S.fromOpcycles
⊢ Epi S.f
Module: Mathlib.Algebra.Homology.ShortComplex.Exact

Goal state before:
pp: case mp
C : Type u_1
inst✝¹ : Category.{v_1, u_1} C
inst✝ : Preadditive C
S : ShortComplex C
hS : S.Exact
⊢ Mono S.g → S.f = 0

pp: case mpr
C : Type u_1
inst✝¹ : Category.{v_1, u_1} C
inst✝ : Preadditive C
S : ShortComplex C
hS : S.Exact
⊢ S.f = 0 → Mono S.g

Tactic:
· intro
    rw [← cancel_mono S.g, zero, zero_comp]

Goal state after:
case mpr
C : Type u_1
inst✝¹ : Category.{v_1, u_1} C
inst✝ : Preadditive C
S : ShortComplex C
hS : S.Exact
⊢ S.f = 0 → Mono S.g
Module: Mathlib.Algebra.Homology.ShortComplex.Exact

Goal state before:
pp: C : Type u_1
inst✝¹ : Category.{v_1, u_1} C
inst✝ : Preadditive C
S : ShortComplex C
s s' : S.Splitting
h : s.s = s'.s
⊢ s = s'

Tactic:
by
  have := s.mono_f
  have eq := s.id
  rw [← s'.id, h, add_left_inj, cancel_mono S.f] at eq
  cases s
  congr

Goal state after:
Module: Mathlib.Algebra.Homology.ShortComplex.Exact

Goal state before:
pp: C : Type u_1
D : Type u_2
inst✝³ : Category.{v_1, u_1} C
inst✝² : Category.{v_2, u_2} D
inst✝¹ : Abelian C
S : ShortComplex C
hS : S.Exact
J : C
f : S.X₂ ⟶ J
inst✝ : Injective J
hf : S.f ≫ f = 0
⊢ S.X₃ ⟶ J

Tactic:
have := hS.mono_fromOpcycles

Goal state after:
C : Type u_1
D : Type u_2
inst✝³ : Category.{v_1, u_1} C
inst✝² : Category.{v_2, u_2} D
inst✝¹ : Abelian C
S : ShortComplex C
hS : S.Exact
J : C
f : S.X₂ ⟶ J
inst✝ : Injective J
hf : S.f ≫ f = 0
this : Mono S.fromOpcycles
⊢ S.X₃ ⟶ J
Module: Mathlib.CategoryTheory.Abelian.Exact

Goal state before:
pp: C : Type u₁
inst✝¹ : Category.{v₁, u₁} C
inst✝ : Abelian C
S : ShortComplex C
⊢ S.Exact ↔ IsIso (imageToKernel S.f S.g ⋯)

Tactic:
rw [S.exact_iff_epi_imageToKernel]

Goal state after:
C : Type u₁
inst✝¹ : Category.{v₁, u₁} C
inst✝ : Abelian C
S : ShortComplex C
⊢ Epi (imageToKernel S.f S.g ⋯) ↔ IsIso (imageToKernel S.f S.g ⋯)
Module: Mathlib.Algebra.Homology.ShortComplex.ExactFunctor

Goal state before:
pp: C : Type u_1
D : Type u_2
inst✝⁸ : Category.{v_1, u_1} C
inst✝⁷ : Category.{v_2, u_2} D
inst✝⁶ : Preadditive C
inst✝⁵ : Preadditive D
F : C ⥤ D
inst✝⁴ : F.Additive
inst✝³ : F.PreservesHomology
inst✝² : HasZeroObject C
inst✝¹ : HasFiniteProducts C
inst✝ : HasKernels C
⊢ PreservesFiniteLimits F

Tactic:
by
  have := fun {X Y : C} (f : X ⟶ Y) ↦ PreservesHomology.preservesKernel F f
  have : HasBinaryBiproducts C := HasBinaryBiproducts.of_hasBinaryProducts
  have : HasEqualizers C := Preadditive.hasEqualizers_of_hasKernels
  have : HasZeroObject D :=
    ⟨F.obj 0, by rw [IsZero.iff_id_eq_zero, ← F.map_id, id_zero, F.map_zero]⟩
  exact preservesFiniteLimits_of_preservesKernels F

Goal state after:
Module: Mathlib.Algebra.Homology.ShortComplex.ExactFunctor

Goal state before:
pp: case refine_1
C : Type u_1
D : Type u_2
inst✝⁴ : Category.{v_1, u_1} C
inst✝³ : Category.{v_2, u_2} D
inst✝² : Abelian C
inst✝¹ : Abelian D
F : C ⥤ D
inst✝ : F.Additive
x✝ : ∀ (S : ShortComplex C), S.ShortExact → (S.map F).ShortExact
hF : ∀ (S : ShortComplex C), S.ShortExact → (S.map F).ShortExact := x✝
X Y : C
f : X ⟶ Y
h : ∀ ⦃X Y : C⦄ (f : X ⟶ Y), PreservesLimit (parallelPair f 0) F
⊢ PreservesLimit (parallelPair f 0) F

Tactic:
exact h f

Goal state after:
Module: Mathlib.Algebra.Homology.ShortComplex.ExactFunctor

Goal state before:
pp: case refine_2
C : Type u_1
D : Type u_2
inst✝⁴ : Category.{v_1, u_1} C
inst✝³ : Category.{v_2, u_2} D
inst✝² : Abelian C
inst✝¹ : Abelian D
F : C ⥤ D
inst✝ : F.Additive
x✝ : ∀ (S : ShortComplex C), S.ShortExact → (S.map F).ShortExact
hF : ∀ (S : ShortComplex C), S.ShortExact → (S.map F).ShortExact := x✝
X Y : C
f : X ⟶ Y
h : ∀ ⦃X Y : C⦄ (f : X ⟶ Y), PreservesColimit (parallelPair f 0) F
⊢ PreservesColimit (parallelPair f 0) F

Tactic:
exact h f

Goal state after:
Module: Mathlib.CategoryTheory.Abelian.FunctorCategory

Goal state before:
pp: C : Type u
inst✝² : Category.{v, u} C
D : Type w
inst✝¹ : Category.{z, w} D
inst✝ : Abelian D
F G : C ⥤ D
α : F ⟶ G
X : C
⊢ (kernel.ι α).app X ≫ 𝟙 (F.obj X) = (PreservesKernel.iso ((evaluation C D).obj X) α).hom ≫ kernel.ι (α.app X)

Tactic:
simp only [Category.comp_id, PreservesKernel.iso_hom]

Goal state after:
C : Type u
inst✝² : Category.{v, u} C
D : Type w
inst✝¹ : Category.{z, w} D
inst✝ : Abelian D
F G : C ⥤ D
α : F ⟶ G
X : C
⊢ (kernel.ι α).app X = kernelComparison α ((evaluation C D).obj X) ≫ kernel.ι (α.app X)
Module: Mathlib.CategoryTheory.Limits.Constructions.Filtered

Goal state before:
pp: case e'_2.e'_6
C : Type u
inst✝³ : Category.{v, u} C
α : Type w
inst✝² : HasFiniteCoproducts C
f : α → C
inst✝¹ : HasColimitsOfShape (Finset (Discrete α)) C
inst✝ : HasCoproduct f
S : Finset (Discrete α)
j : ↥S
e_1✝ : (f (↑j).as ⟶ ∐ f) = ((Discrete.functor f).obj ↑j ⟶ (colimit.cocone (Discrete.functor f)).pt)
e_3✝ : f (↑j).as = (Discrete.functor f).obj ↑j
e_4✝ : colimit (liftToFinsetObj (Discrete.functor f)) = (liftToFinsetColimitCocone (Discrete.functor f)).cocone.pt
⊢ Sigma.ι (fun x ↦ f (↑x).as) j ≫ colimit.ι (liftToFinsetObj (Discrete.functor f)) S =
    (liftToFinsetColimitCocone (Discrete.functor f)).cocone.ι.app ↑j

Tactic:
simp [← colimit.w (liftToFinsetObj _) (homOfLE (x := {j.1}) (y := S) (by simp))]

Goal state after:
Module: Mathlib.CategoryTheory.Limits.Presheaf

Goal state before:
pp: C : Type u₁
inst✝¹ : Category.{v₁, u₁} C
ℰ : Type u₂
inst✝ : Category.{v₂, u₂} ℰ
A : C ⥤ ℰ
E : ℰ
X Y : C
f : X ⟶ Y
g : uliftYoneda.{max w v₂, v₁, u₁}.obj Y ⟶ (restrictedULiftYoneda A).obj E
⊢ A.map f ≫ (uliftYonedaEquiv g).down = (uliftYonedaEquiv (uliftYoneda.{max v₂ w, v₁, u₁}.map f ≫ g)).down

Tactic:
have := (g.naturality_apply f.op) (ULift.up (𝟙 Y))
  dsimp [uliftYonedaEquiv, uliftYoneda] at this ⊢
  cat_disch

Goal state after:
Module: Mathlib.CategoryTheory.Abelian.Subobject

Goal state before:
pp: case refine_2
C : Type u
inst✝¹ : Category.{v, u} C
inst✝ : Abelian C
X A : C
f : A ⟶ X
hf : Mono f
⊢ ((kernelOrderHom X).comp (cokernelOrderHom X)) (Subobject.mk f) = OrderHom.id (Subobject.mk f)

Tactic:
dsimp only [OrderHom.comp_coe, Function.comp_apply, cokernelOrderHom_coe, Subobject.lift_mk,
      kernelOrderHom_coe, OrderHom.id_coe, id, unop_op, Quiver.Hom.unop_op]

Goal state after:
case refine_2
C : Type u
inst✝¹ : Category.{v, u} C
inst✝ : Abelian C
X A : C
f : A ⟶ X
hf : Mono f
⊢ Subobject.mk (kernel.ι (cokernel.π f)) = Subobject.mk f