mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.AlgebraicTopology.SimplicialObject.ChainHomotopy

Goal state before:
pp: C : Type u
inst✝¹ : Category.{v, u} C
inst✝ : Preadditive C
X Y : SimplicialObject C
f g : X ⟶ Y
H : Homotopy f g
n : ℕ
α : Fin (n + 1) × Fin (n + 2) → (X _⦋n + 1⦌ ⟶ Y _⦋n + 1⦌) := fun x ↦ (-1) ^ (↑x.1 + ↑x.2) • X.δ x.2 ≫ H.h x.1
β : Fin (n + 3) × Fin (n + 2) → (X _⦋n + 1⦌ ⟶ Y _⦋n + 1⦌) := fun x ↦ (-1) ^ (↑x.1 + ↑x.2) • H.h x.2 ≫ Y.δ x.1
h₂ : ∀ (x : Fin (n + 1) × Fin (n + 2)), x.1.castSucc < x.2 → α x = -β (x.2.succ, x.1.castSucc)
S : Finset (Fin (n + 1) × Fin (n + 2)) := {x | x.1.castSucc < x.2}
γ₁ : Fin (n + 1) × Fin (n + 2) → Fin (n + 2 + 1) × Fin (n + 1 + 1) := fun x ↦ (x.2.castSucc, x.1.succ)
γ₂ : Fin (n + 1) × Fin (n + 2) → Fin (n + 2 + 1) × Fin (n + 1 + 1) := fun x ↦ (x.2.succ, x.1.castSucc)
γ₃ : Fin (n + 1) → Fin (n + 1 + 1 + 1) × Fin (n + 1 + 1) := fun i ↦ (i.castSucc.succ, i.succ)
γ₄ : Fin (n + 1) → Fin (n + 1 + 1 + 1) × Fin (n + 1 + 1) := fun i ↦ (i.castSucc.succ, i.castSucc)
hγ₁ : Function.Injective γ₁
hγ₂ : Function.Injective γ₂
hγ₃ : Function.Injective γ₃
hγ₄ : Function.Injective γ₄
eq₁ : H.h 0 ≫ Y.δ 0 = β (0, 0)
eq₂ : H.h (Fin.last (n + 1)) ≫ Y.δ (Fin.last (n + 1 + 1)) = -β (Fin.last (n + 2), Fin.last (n + 1))
x : Fin (n + 1) × Fin (n + 2)
hx : x ∈ Sᶜ
⊢ x.2 ≤ x.1.castSucc

Tactic:
by simpa [S] using hx

Goal state after:
Module: Mathlib.AlgebraicTopology.SimplicialSet.AnodyneExtensions.RelativeCellComplex

Goal state before:
pp: case a
X : SSet
A : X.Subcomplex
P : A.Pairing
ι : Type v
inst✝² : LinearOrder ι
f : P.RankFunction ι
inst✝¹ : OrderBot ι
inst✝ : SuccOrder ι
m : ι
hm : Order.IsSuccLimit m
⊢ A ⊔ ⨆ j, ⨆ (_ : j < m), ⨆ c, (↑(P.p c.s)).subcomplex ≤ ⨆ i, f.filtration ↑i

Tactic:
simp only [sup_le_iff, iSup_le_iff, ← f.filtration_bot]

Goal state after:
case a
X : SSet
A : X.Subcomplex
P : A.Pairing
ι : Type v
inst✝² : LinearOrder ι
f : P.RankFunction ι
inst✝¹ : OrderBot ι
inst✝ : SuccOrder ι
m : ι
hm : Order.IsSuccLimit m
⊢ f.filtration ⊥ ≤ ⨆ i, f.filtration ↑i ∧ ∀ i < m, ∀ (i_2 : f.Cell i), (↑(P.p i_2.s)).subcomplex ≤ ⨆ i, f.filtration ↑i
Module: Mathlib.AlgebraicTopology.SimplicialObject.ChainHomotopy

Goal state before:
pp: C : Type u
inst✝¹ : Category.{v, u} C
inst✝ : Preadditive C
X Y : SimplicialObject C
f g : X ⟶ Y
H : Homotopy f g
n : ℕ
α : Fin (n + 1) × Fin (n + 2) → (X _⦋n + 1⦌ ⟶ Y _⦋n + 1⦌) := fun x ↦ (-1) ^ (↑x.1 + ↑x.2) • X.δ x.2 ≫ H.h x.1
β : Fin (n + 3) × Fin (n + 2) → (X _⦋n + 1⦌ ⟶ Y _⦋n + 1⦌) := fun x ↦ (-1) ^ (↑x.1 + ↑x.2) • H.h x.2 ≫ Y.δ x.1
h₂ : ∀ (x : Fin (n + 1) × Fin (n + 2)), x.1.castSucc < x.2 → α x = -β (x.2.succ, x.1.castSucc)
S : Finset (Fin (n + 1) × Fin (n + 2)) := {x | x.1.castSucc < x.2}
γ₁ : Fin (n + 1) × Fin (n + 2) → Fin (n + 2 + 1) × Fin (n + 1 + 1) := fun x ↦ (x.2.castSucc, x.1.succ)
γ₂ : Fin (n + 1) × Fin (n + 2) → Fin (n + 2 + 1) × Fin (n + 1 + 1) := fun x ↦ (x.2.succ, x.1.castSucc)
γ₃ : Fin (n + 1) → Fin (n + 1 + 1 + 1) × Fin (n + 1 + 1) := fun i ↦ (i.castSucc.succ, i.succ)
γ₄ : Fin (n + 1) → Fin (n + 1 + 1 + 1) × Fin (n + 1 + 1) := fun i ↦ (i.castSucc.succ, i.castSucc)
hγ₁ : Function.Injective γ₁
hγ₂ : Function.Injective γ₂
hγ₃ : Function.Injective γ₃
hγ₄ : Function.Injective γ₄
eq₁ : H.h 0 ≫ Y.δ 0 = β (0, 0)
eq₂ : H.h (Fin.last (n + 1)) ≫ Y.δ (Fin.last (n + 1 + 1)) = -β (Fin.last (n + 2), Fin.last (n + 1))
eq₃ : ∑ x ∈ Sᶜ, α x = -∑ y ∈ Finset.image γ₁ Sᶜ, β y
x : Fin (n + 1) × Fin (n + 2)
hx : x ∈ S
⊢ x.1.castSucc < x.2

Tactic:
by simpa [S] using hx

Goal state after:
Module: Mathlib.CategoryTheory.SmallRepresentatives

Goal state before:
pp: Ω : Type w
C : Type u
inst✝ : Category.{v, u} C
h : CoreSmallCategoryOfSet Ω C
x✝ : ↑h.smallCategoryOfSet.obj
⊢ h.homEquiv (𝟙 x✝) = 𝟙 (h.objEquiv x✝)

Tactic:
rw [SmallCategoryOfSet.id_def]

Goal state after:
Ω : Type w
C : Type u
inst✝ : Category.{v, u} C
h : CoreSmallCategoryOfSet Ω C
x✝ : ↑h.smallCategoryOfSet.obj
⊢ h.homEquiv (h.smallCategoryOfSet.id x✝) = 𝟙 (h.objEquiv x✝)
Module: Mathlib.CategoryTheory.SmallRepresentatives

Goal state before:
pp: Ω : Type w
C : Type u
inst✝ : Category.{v, u} C
h : CoreSmallCategoryOfSet Ω C
⊢ Function.Bijective h.functor.mapArrow.obj

Tactic:
constructor
    · rintro ⟨x, y, f⟩ ⟨x', y', g⟩ hfg
      obtain rfl : x = x' := by simpa using! congr_arg Arrow.leftFunc.obj hfg
      obtain rfl : y = y' := by simpa using! congr_arg Arrow.rightFunc.obj hfg
      obtain rfl : f = g := by simpa [Arrow.mk_eq_mk_iff] using! hfg
      rfl
    · rintro ⟨X, Y, f⟩
      obtain ⟨x, rfl⟩ := h.objEquiv.surjective X
      obtain ⟨y, rfl⟩ := h.objEquiv.surjective Y
      obtain ⟨f, rfl⟩ := h.homEquiv.surjective f
      exact ⟨Arrow.mk f, rfl⟩

Goal state after:
Module: Mathlib.AlgebraicTopology.SimplicialSet.AnodyneExtensions.RelativeCellComplex

Goal state before:
pp: case inr
X : SSet
A : X.Subcomplex
P : A.Pairing
ι : Type v
inst✝¹ : LinearOrder ι
f : P.RankFunction ι
inst✝ : P.IsProper
j : ι
x : f.Cell j
hs✝ :
  (ConcreteCategory.hom (x.ιSigmaStdSimplex.app (op ⦋x.dim + 1⦌)))
      (stdSimplex.objEquiv.symm (𝟙 (unop (op ⦋x.dim + 1⦌)))) ∈
    (f.sigmaStdSimplex j).nonDegenerate (x.dim + 1)
hs : Mono (𝟙 (unop (op ⦋x.dim + 1⦌)))
hs'✝ :
  (ConcreteCategory.hom (x.ιSigmaStdSimplex.app (op ⦋x.dim + 1⦌)))
      (stdSimplex.objEquiv.symm (𝟙 (unop (op ⦋x.dim + 1⦌)))) ∉
    (range (f.m j)).obj (op ⦋x.dim + 1⦌)
hs' : stdSimplex.objEquiv.symm (𝟙 (unop (op ⦋x.dim + 1⦌))) ∉ Λ[x.dim + 1, x.index].obj (op ⦋x.dim + 1⦌)
⊢ ∃ c,
    N.mk
          ((ConcreteCategory.hom (x.ιSigmaStdSimplex.app (op ⦋x.dim + 1⦌)))
            (stdSimplex.objEquiv.symm (𝟙 (unop (op ⦋x.dim + 1⦌)))))
          hs✝ hs'✝ =
        Cell.type₁ f c ∨
      N.mk
          ((ConcreteCategory.hom (x.ιSigmaStdSimplex.app (op ⦋x.dim + 1⦌)))
            (stdSimplex.objEquiv.symm (𝟙 (unop (op ⦋x.dim + 1⦌)))))
          hs✝ hs'✝ =
        Cell.type₂ f c

Tactic:
exact ⟨x, Or.inl rfl⟩

Goal state after:
Module: Mathlib.AlgebraicTopology.SimplicialSet.AnodyneExtensions.RelativeCellComplex

Goal state before:
pp: case refine_2
X : SSet
A : X.Subcomplex
P : A.Pairing
ι : Type v
inst✝³ : LinearOrder ι
f : P.RankFunction ι
inst✝² : P.IsProper
inst✝¹ : SuccOrder ι
inst✝ : NoMaxOrder ι
j : ι
x✝ : SimplexCategoryᵒᵖ
d : ℕ
y : ↑((f.filtration j).obj (op ⦋d⦌))
x : f.Cell j
b : Δ[x.dim + 1] _⦋d⦌
h : ⟨↑y, ⋯⟩ = (ConcreteCategory.hom ((f.b j).app (op ⦋d⦌))) ((ConcreteCategory.hom (x.ιSigmaStdSimplex.app (op ⦋d⦌))) b)
hb : b ∈ Λ[x.dim + 1, x.index].obj (op ⦋d⦌)
⊢ (ConcreteCategory.hom ((f.m j).app (op ⦋d⦌))) ((ConcreteCategory.hom (x.ιSigmaHorn.app (op ⦋d⦌))) ⟨b, hb⟩) =
    (ConcreteCategory.hom (x.ιSigmaStdSimplex.app (op ⦋d⦌))) b

Tactic:
· rw [← NatTrans.comp_app_apply]
      simp

Goal state after:
Module: Mathlib.AlgebraicTopology.SimplicialSet.AnodyneExtensions.RelativeCellComplex

Goal state before:
pp: case inl
X : SSet
A : X.Subcomplex
P : A.Pairing
ι : Type v
inst✝³ : LinearOrder ι
f : P.RankFunction ι
inst✝² : P.IsProper
inst✝¹ : SuccOrder ι
inst✝ : NoMaxOrder ι
j : ι
t : (range (f.m j)).N
c : f.Cell j
h : f.mapN (Cell.type₁ f c) = f.mapN t
⊢ Cell.type₁ f c = t

Tactic:
obtain ⟨c', rfl | rfl⟩ := f.exists_or_of_range_m_N t

Goal state after:
case inl.inl
X : SSet
A : X.Subcomplex
P : A.Pairing
ι : Type v
inst✝³ : LinearOrder ι
f : P.RankFunction ι
inst✝² : P.IsProper
inst✝¹ : SuccOrder ι
inst✝ : NoMaxOrder ι
j : ι
c c' : f.Cell j
h : f.mapN (Cell.type₁ f c) = f.mapN (Cell.type₁ f c')
⊢ Cell.type₁ f c = Cell.type₁ f c'

case inl.inr
X : SSet
A : X.Subcomplex
P : A.Pairing
ι : Type v
inst✝³ : LinearOrder ι
f : P.RankFunction ι
inst✝² : P.IsProper
inst✝¹ : SuccOrder ι
inst✝ : NoMaxOrder ι
j : ι
c c' : f.Cell j
h : f.mapN (Cell.type₁ f c) = f.mapN (Cell.type₂ f c')
⊢ Cell.type₁ f c = Cell.type₂ f c'
Module: Mathlib.AlgebraicTopology.SimplicialSet.AnodyneExtensions.RelativeCellComplex

Goal state before:
pp: case inr
X : SSet
A : X.Subcomplex
P : A.Pairing
ι : Type v
inst✝³ : LinearOrder ι
f : P.RankFunction ι
inst✝² : P.IsProper
inst✝¹ : SuccOrder ι
inst✝ : NoMaxOrder ι
j : ι
t : (range (f.m j)).N
c : f.Cell j
h : f.mapN (Cell.type₂ f c) = f.mapN t
⊢ Cell.type₂ f c = t

Tactic:
obtain ⟨c', rfl | rfl⟩ := f.exists_or_of_range_m_N t

Goal state after:
case inr.inl
X : SSet
A : X.Subcomplex
P : A.Pairing
ι : Type v
inst✝³ : LinearOrder ι
f : P.RankFunction ι
inst✝² : P.IsProper
inst✝¹ : SuccOrder ι
inst✝ : NoMaxOrder ι
j : ι
c c' : f.Cell j
h : f.mapN (Cell.type₂ f c) = f.mapN (Cell.type₁ f c')
⊢ Cell.type₂ f c = Cell.type₁ f c'

case inr.inr
X : SSet
A : X.Subcomplex
P : A.Pairing
ι : Type v
inst✝³ : LinearOrder ι
f : P.RankFunction ι
inst✝² : P.IsProper
inst✝¹ : SuccOrder ι
inst✝ : NoMaxOrder ι
j : ι
c c' : f.Cell j
h : f.mapN (Cell.type₂ f c) = f.mapN (Cell.type₂ f c')
⊢ Cell.type₂ f c = Cell.type₂ f c'
Module: Mathlib.CategoryTheory.Monoidal.Limits.Shapes.Pullback

Goal state before:
pp: C : Type u
inst✝² : Category.{v, u} C
inst✝¹ : MonoidalCategory C
inst✝ : HasPushouts C
X Y Z : C
f : X ⟶ Y
g : X ⟶ Z
Q : C
⊢ Q ◁ f ≫ Q ◁ pushout.inl f g = Q ◁ g ≫ Q ◁ pushout.inr f g

Tactic:
by
  simp [← MonoidalCategory.whiskerLeft_comp, pushout.condition]

Goal state after:
Module: Mathlib.AlgebraicTopology.SimplicialSet.AnodyneExtensions.UnionProd

Goal state before:
pp: m : ℕ
k : Fin (m + 1)
n : ℕ
x : (Λ[m + 1, k.castSucc].unionProd ∂Δ[n]).N
d : ℕ
hd : x.dim = d
i : Fin (m + 2)
hi : i ≠ k.castSucc
⊢ i ∈ Set.range ⇑(x.cast hd).simplex.1

Tactic:
by
  subst hd
  have := x.notMem
  simp [Subcomplex.mem_unionProd_iff, mem_horn_iff_notMem_range] at this
  tauto

Goal state after:
Module: Mathlib.AlgebraicTopology.SimplicialSet.AnodyneExtensions.UnionProd

Goal state before:
pp: case refine_1.inr
m : ℕ
k : Fin (m + 1)
n : ℕ
x : (Λ[m + 1, k.castSucc].unionProd ∂Δ[n]).N
d : ℕ
hd : x.dim = d
i : Fin (d + 1)
h✝ : k.succ ≤ (x.cast hd).simplex.1 i
h : k.succ = (x.cast hd).simplex.1 i
⊢ min x hd ≤ i

Tactic:
exact Finset.min'_le _ _ (by simpa using h.symm)

Goal state after:
Module: Mathlib.CategoryTheory.Monoidal.PushoutProduct

Goal state before:
pp: C : Type u
inst✝⁶ : Category.{v, u} C
inst✝⁵ : HasPushouts C
inst✝⁴ : MonoidalCategory C
X₁ X₂ X₃ : Arrow C
W : C
inst✝³ : PreservesColimit (span (X₁.hom ▷ X₂.left) (X₁.left ◁ X₂.hom)) (tensorRight X₃.left)
inst✝² : PreservesColimit (span (X₁.hom ▷ X₂.left) (X₁.left ◁ X₂.hom)) (tensorRight X₃.right)
inst✝¹ : PreservesColimit (span (X₂.hom ▷ X₃.left) (X₂.left ◁ X₃.hom)) (tensorLeft X₁.left)
inst✝ : PreservesColimit (span (X₂.hom ▷ X₃.left) (X₂.left ◁ X₃.hom)) (tensorLeft X₁.right)
⊢ ((X₁ □ X₂) □ X₃) ≅ X₁ □ X₂ □ X₃

Tactic:
refine Arrow.isoMk ?_ (α_ _ _ _) ?_

Goal state after:
case refine_1
C : Type u
inst✝⁶ : Category.{v, u} C
inst✝⁵ : HasPushouts C
inst✝⁴ : MonoidalCategory C
X₁ X₂ X₃ : Arrow C
W : C
inst✝³ : PreservesColimit (span (X₁.hom ▷ X₂.left) (X₁.left ◁ X₂.hom)) (tensorRight X₃.left)
inst✝² : PreservesColimit (span (X₁.hom ▷ X₂.left) (X₁.left ◁ X₂.hom)) (tensorRight X₃.right)
inst✝¹ : PreservesColimit (span (X₂.hom ▷ X₃.left) (X₂.left ◁ X₃.hom)) (tensorLeft X₁.left)
inst✝ : PreservesColimit (span (X₂.hom ▷ X₃.left) (X₂.left ◁ X₃.hom)) (tensorLeft X₁.right)
⊢ ((X₁ □ X₂) □ X₃).left ≅ (X₁ □ X₂ □ X₃).left

case refine_2
C : Type u
inst✝⁶ : Category.{v, u} C
inst✝⁵ : HasPushouts C
inst✝⁴ : MonoidalCategory C
X₁ X₂ X₃ : Arrow C
W : C
inst✝³ : PreservesColimit (span (X₁.hom ▷ X₂.left) (X₁.left ◁ X₂.hom)) (tensorRight X₃.left)
inst✝² : PreservesColimit (span (X₁.hom ▷ X₂.left) (X₁.left ◁ X₂.hom)) (tensorRight X₃.right)
inst✝¹ : PreservesColimit (span (X₂.hom ▷ X₃.left) (X₂.left ◁ X₃.hom)) (tensorLeft X₁.left)
inst✝ : PreservesColimit (span (X₂.hom ▷ X₃.left) (X₂.left ◁ X₃.hom)) (tensorLeft X₁.right)
⊢ Iso.hom ?refine_1 ≫ (X₁ □ X₂ □ X₃).hom = ((X₁ □ X₂) □ X₃).hom ≫ (α_ X₁.right X₂.right X₃.right).hom
Module: Mathlib.CategoryTheory.Monoidal.PushoutProduct

Goal state before:
pp: C : Type u
inst✝⁶ : Category.{v, u} C
inst✝⁵ : HasPushouts C
inst✝⁴ : MonoidalCategory C
X₁ X₂ X₃ : Arrow C
W : C
inst✝³ : PreservesColimit (span (X₁.hom ▷ X₂.left) (X₁.left ◁ X₂.hom)) (tensorRight X₃.left)
inst✝² : PreservesColimit (span (X₁.hom ▷ X₂.left) (X₁.left ◁ X₂.hom)) (tensorRight X₃.right)
inst✝¹ : PreservesColimit (span (X₂.hom ▷ X₃.left) (X₂.left ◁ X₃.hom)) (tensorLeft X₁.left)
inst✝ : PreservesColimit (span (X₂.hom ▷ X₃.left) (X₂.left ◁ X₃.hom)) (tensorLeft X₁.right)
⊢ (tensorLeft X₁.left).map
        (pushout.inl (((curriedTensor C).map X₂.hom).app X₃.left) (((curriedTensor C).obj X₂.left).map X₃.hom)) ≫
      ((curriedTensor C).map X₁.hom).app (X₂ □ X₃).left ≫
        Arrow.Hom.left (whiskerLeftIso X₂ X₃).hom ≫
          pushout.desc
            (pushout.inl (((curriedTensor C).map (X₁ □ X₂).hom).app X₃.left)
              (((curriedTensor C).obj (X₁ □ X₂).left).map X₃.hom))
            (pushout.inl (((curriedTensor C).map X₁.hom).app X₂.left) (((curriedTensor C).obj X₁.left).map X₂.hom) ▷
                X₃.right ≫
              pushout.inr (((curriedTensor C).map (X₁ □ X₂).hom).app X₃.left)
                (((curriedTensor C).obj (X₁ □ X₂).left).map X₃.hom))
            ⋯ =
    (tensorLeft X₁.left).map
        (pushout.inl (((curriedTensor C).map X₂.hom).app X₃.left) (((curriedTensor C).obj X₂.left).map X₃.hom)) ≫
      ((curriedTensor C).obj X₁.left).map (X₂ □ X₃).hom ≫
        (α_ X₁.left X₂.right X₃.right).inv ≫
          pushout.inr (((curriedTensor C).map X₁.hom).app X₂.left) (((curriedTensor C).obj X₁.left).map X₂.hom) ▷
              X₃.right ≫
            pushout.inr (((curriedTensor C).map (X₁ □ X₂).hom).app X₃.left)
              (((curriedTensor C).obj (X₁ □ X₂).left).map X₃.hom)

Tactic:
by simp [whisker_exchange_assoc,
            Limits.pushout.associator_inv_naturality_right_condition, ← whiskerLeft_comp_assoc]

Goal state after:
Module: Mathlib.AlgebraicTopology.SimplicialSet.AnodyneExtensions.UnionProd

Goal state before:
pp: case refine_2
m : ℕ
k : Fin (m + 1)
n : ℕ
x : (Λ[m + 1, k.castSucc].unionProd ∂Δ[n]).N
d : ℕ
hd : x.dim = d + 1
l : Fin (d + 1)
hl : IsIndex x hd l.succ
y : Fin (d + 1)
hy : (x.cast hd).simplex.1 y.castSucc = k.succ
this : y < l
⊢ False

Tactic:
grind [(hl.succ_le_simplex_fst_iff y.castSucc).1 hy.symm.le]

Goal state after:
Module: Mathlib.AlgebraicTopology.SimplicialSet.CoherentIso

Goal state before:
pp: C : Type u
inst✝ : Category.{v, u} C
F : WalkingIso ⥤ C
X Y : WalkingIso
f : X ⟶ Y
⊢ ((fun p ↦ fromIso p.snd.snd) ((fun F ↦ ⟨F.obj zero, ⟨F.obj one, toIso F⟩⟩) F)).map f = eqToHom ⋯ ≫ F.map f ≫ eqToHom ⋯

Tactic:
induction X <;>
      induction Y <;>
      simp [Codiscrete.eq_id]

Goal state after:
case zero.one
C : Type u
inst✝ : Category.{v, u} C
F : WalkingIso ⥤ C
f : zero ⟶ one
⊢ F.map iso.hom = F.map f

case one.zero
C : Type u
inst✝ : Category.{v, u} C
F : WalkingIso ⥤ C
f : one ⟶ zero
⊢ F.map iso.inv = F.map f
Module: Mathlib.AlgebraicTopology.SimplicialSet.AnodyneExtensions.UnionProd

Goal state before:
pp: case pos.snd
m : ℕ
k : Fin (m + 1)
n : ℕ
s : Type₁ k n
ht : IsType₂ s.δ
⊢ (s.x.cast ⋯).simplex.2 s.index.succ = ((objEquiv (s.x.cast ⋯).simplex) s.index.castSucc).2

Tactic:
exact s.isIndex.simplex_snd_succ

Goal state after:
Module: Mathlib.AlgebraicTopology.SimplicialSet.Homology.HomologyZero

Goal state before:
pp: case refine_1
C : Type u
inst✝² : Category.{v, u} C
inst✝¹ : HasCoproducts C
inst✝ : Preadditive C
X : SSet
R : C
⊢ parallelPair ((sigmaConst.obj R).map (SimplicialObject.δ X 1) - (sigmaConst.obj R).map (SimplicialObject.δ X 0)) 0 ≅
    parallelPair ((X.chainComplex R).d 1 0) 0

pp: case refine_2
C : Type u
inst✝² : Category.{v, u} C
inst✝¹ : HasCoproducts C
inst✝ : Preadditive C
X : SSet
R : C
⊢ (Cocone.precompose (Iso.inv ?refine_1)).obj
      (Preadditive.cokernelCoforkOfCofork (Cofork.ofπ ((sigmaConst.obj R).map (↾π₀.mk)) ⋯)) ≅
    CokernelCofork.ofπ (π₀.fromChainComplexXZero X R) ⋯

Tactic:
· refine parallelPair.ext (-Iso.refl _) (Iso.refl _) ?_ (by simp)
    simp [chainComplex, SSet.chainComplexFunctor, sub_eq_neg_add]

Goal state after:
case refine_2
C : Type u
inst✝² : Category.{v, u} C
inst✝¹ : HasCoproducts C
inst✝ : Preadditive C
X : SSet
R : C
⊢ (Cocone.precompose
          (parallelPair.ext
              (-Iso.refl
                  ((parallelPair
                        ((sigmaConst.obj R).map (SimplicialObject.δ X 1) -
                          (sigmaConst.obj R).map (SimplicialObject.δ X 0))
                        0).obj
                    WalkingParallelPair.zero))
              (Iso.refl
                ((parallelPair
                      ((sigmaConst.obj R).map (SimplicialObject.δ X 1) -
                        (sigmaConst.obj R).map (SimplicialObject.δ X 0))
                      0).obj
                  WalkingParallelPair.one))
              ⋯ ⋯).inv).obj
      (Preadditive.cokernelCoforkOfCofork (Cofork.ofπ ((sigmaConst.obj R).map (↾π₀.mk)) ⋯)) ≅
    CokernelCofork.ofπ (π₀.fromChainComplexXZero X R) ⋯
Module: Mathlib.AlgebraicTopology.SimplicialSet.Homology.Nondegenerate

Goal state before:
pp: C : Type u
inst✝² : Category.{v, u} C
inst✝¹ : HasCoproducts C
inst✝ : Preadditive C
X : SSet
R : C
n : ℕ
x : X _⦋n⦌
hx : x ∈ X.degenerate n
⊢ X.ιNormalizedChainComplex x = 0

Tactic:
rw [← cancel_mono ((X.fromNormalizedChainComplex R).f n), zero_comp,
    ιNormalizedChainComplex_fromNormalizedChainComplex_f]

Goal state after:
C : Type u
inst✝² : Category.{v, u} C
inst✝¹ : HasCoproducts C
inst✝ : Preadditive C
X : SSet
R : C
n : ℕ
x : X _⦋n⦌
hx : x ∈ X.degenerate n
⊢ X.ιChainComplex x ≫ PInfty.f n = 0
Module: Mathlib.AlgebraicTopology.SimplicialSet.Homology.Nondegenerate

Goal state before:
pp: C : Type u
inst✝⁴ : Category.{v, u} C
inst✝³ : HasCoproducts C
inst✝² : Preadditive C
X : SSet
R : C
inst✝¹ : CategoryWithHomology C
n d : ℕ
inst✝ : X.HasDimensionLT d
h : d ≤ n
⊢ ExactAt (X.normalizedChainComplex R) n

Tactic:
exact .of_isZero (X.isZero_normalizedChainComplex_X_of_hasDimensionLT R n d)

Goal state after:
Module: Mathlib.AlgebraicTopology.SimplicialSet.NonDegenerateSimplicesColimit

Goal state before:
pp: X : SSet
n : ℕ
x : X _⦋n⦌
⊢ x ∈ X.nonDegenerate n → x ∈ (⨆ i, i.subcomplex).obj (op ⦋n⦌)

Tactic:
hx

Goal state after:
X : SSet
n : ℕ
x : X _⦋n⦌
hx : x ∈ X.nonDegenerate n
⊢ x ∈ (⨆ i, i.subcomplex).obj (op ⦋n⦌)
Module: Mathlib.AlgebraicTopology.SimplicialSet.KanComplex.MulStruct

Goal state before:
pp: X : SSet
n : ℕ
x : X _⦋0⦌
s : X.PtSimplex n x
Y : SSet
φ : Y ⟶ Δ[n]
inst✝ : Y.HasDimensionLT n
⊢ Subcomplex.range φ ≤ ∂Δ[n]

Tactic:
rw [stdSimplex.le_boundary_iff]

Goal state after:
X : SSet
n : ℕ
x : X _⦋0⦌
s : X.PtSimplex n x
Y : SSet
φ : Y ⟶ Δ[n]
inst✝ : Y.HasDimensionLT n
⊢ Subcomplex.range φ ≠ ⊤
Module: Mathlib.AlgebraicTopology.SimplicialSet.TopAdj

Goal state before:
pp: ⊢ stdSimplexHomeomorphI.symm 0 = stdSimplex.vertex 0

Tactic:
simp [← TopCat.stdSimplexHomeomorphI_vertex_zero]

Goal state after:
Module: Mathlib.SetTheory.Cardinal.CountableCover

Goal state before:
pp: α ι : Type u
a : Cardinal.{u}
inst✝¹ : Countable ι
f : ι → Set α
l : Filter ι
inst✝ : l.NeBot
t : Set α
ht : ∀ x ∈ t, ∀ᶠ (i : ι) in l, x ∈ f i
h'f : ∀ (i : ι), #↑(f i) ≤ a
ha : ℵ₀ ≤ a
x : α
⊢ x ∈ t → x ∈ ⋃ i, f i

Tactic:
hx

Goal state after:
α ι : Type u
a : Cardinal.{u}
inst✝¹ : Countable ι
f : ι → Set α
l : Filter ι
inst✝ : l.NeBot
t : Set α
ht : ∀ x ∈ t, ∀ᶠ (i : ι) in l, x ∈ f i
h'f : ∀ (i : ι), #↑(f i) ≤ a
ha : ℵ₀ ≤ a
x : α
hx : x ∈ t
⊢ x ∈ ⋃ i, f i
Module: Mathlib.SetTheory.Cardinal.CountableCover

Goal state before:
pp: case ht
α : Type u
ι : Type v
a : Cardinal.{u}
inst✝¹ : Countable ι
f : ι → Set α
l : Filter ι
inst✝ : l.NeBot
t : Set α
ht : ∀ x ∈ t, ∀ᶠ (i : ι) in l, x ∈ f i
h'f : ∀ (i : ι), #↑(f i) ≤ a
g : ULift.{u, v} ι → Set (ULift.{v, u} α) := (fun x ↦ ULift.down ⁻¹' x) ∘ f ∘ ULift.down
l' : Filter (ULift.{u, v} ι) := Filter.map ULift.up l
x : ULift.{v, u} α
⊢ x ∈ ULift.down ⁻¹' t → ∀ᶠ (i : ULift.{u, v} ι) in l', x ∈ g i

Tactic:
hx

Goal state after:
case ht
α : Type u
ι : Type v
a : Cardinal.{u}
inst✝¹ : Countable ι
f : ι → Set α
l : Filter ι
inst✝ : l.NeBot
t : Set α
ht : ∀ x ∈ t, ∀ᶠ (i : ι) in l, x ∈ f i
h'f : ∀ (i : ι), #↑(f i) ≤ a
g : ULift.{u, v} ι → Set (ULift.{v, u} α) := (fun x ↦ ULift.down ⁻¹' x) ∘ f ∘ ULift.down
l' : Filter (ULift.{u, v} ι) := Filter.map ULift.up l
x : ULift.{v, u} α
hx : x ∈ ULift.down ⁻¹' t
⊢ ∀ᶠ (i : ULift.{u, v} ι) in l', x ∈ g i
Module: Mathlib.SetTheory.Cardinal.CountableCover

Goal state before:
pp: case a
α : Type u
ι : Type v
a : Cardinal.{u}
inst✝¹ : Countable ι
f : ι → Set α
l : Filter ι
inst✝ : l.NeBot
ht : ∀ (x : α), ∀ᶠ (i : ι) in l, x ∈ f i
h'f : ∀ (i : ι), #↑(f i) = a
⊢ a ≤ #α

Tactic:
obtain ⟨i⟩ : Nonempty ι := nonempty_of_neBot l
    rw [← (h'f i)]
    exact mk_set_le (f i)

Goal state after:
Module: Mathlib.Analysis.Normed.Module.Connected

Goal state before:
pp: E : Type u_1
inst✝⁴ : AddCommGroup E
inst✝³ : Module ℝ E
inst✝² : TopologicalSpace E
inst✝¹ : ContinuousAdd E
inst✝ : ContinuousSMul ℝ E
h : 1 < Module.rank ℝ E
s : Set E
hs : s.Countable
this : Nontrivial E
a : E
ha : a ∈ sᶜ
b : E
hb : b ∈ sᶜ
hab : a ≠ b
c : E := 2⁻¹ • (a + b)
x : E := 2⁻¹ • (b - a)
Ia : c - x = a
Ib : c + x = b
x_ne_zero : x ≠ 0
y : E
hy : LinearIndependent ℝ ![x, y]
A : {t | ([c + x -[ℝ] c + t • y] ∩ s).Nonempty}.Countable
B : {t | ([c - x -[ℝ] c + t • y] ∩ s).Nonempty}.Countable
t : ℝ
z : E := c + t • y
ht : [c + x -[ℝ] c + t • y] ∩ s = ∅ ∧ [c - x -[ℝ] c + t • y] ∩ s = ∅
⊢ JoinedIn sᶜ a z

Tactic:
apply JoinedIn.of_segment_subset

Goal state after:
E : Type u_1
inst✝⁴ : AddCommGroup E
inst✝³ : Module ℝ E
inst✝² : TopologicalSpace E
inst✝¹ : ContinuousAdd E
inst✝ : ContinuousSMul ℝ E
h : 1 < Module.rank ℝ E
s : Set E
hs : s.Countable
this : Nontrivial E
a : E
ha : a ∈ sᶜ
b : E
hb : b ∈ sᶜ
hab : a ≠ b
c : E := ⋯
x : E := ⋯
Ia : c - x = a
Ib : c + x = b
x_ne_zero : x ≠ 0
y : E
hy : LinearIndependent ℝ ![x, y]
A : {t | ([c + x -[ℝ] c + t • y] ∩ s).Nonempty}.Countable
B : {t | ([c - x -[ℝ] c + t • y] ∩ s).Nonempty}.Countable
t : ℝ
z : E := ⋯
ht : [c + x -[ℝ] c + t • y] ∩ s = ∅ ∧ [c - x -[ℝ] c + t • y] ∩ s = ∅
⊢ [a -[ℝ] z] ⊆ sᶜ
Module: Mathlib.Analysis.Normed.Module.Connected

Goal state before:
pp: E : Type u_1
inst✝⁴ : AddCommGroup E
inst✝³ : Module ℝ E
inst✝² : TopologicalSpace E
inst✝¹ : ContinuousAdd E
inst✝ : ContinuousSMul ℝ E
h : 1 < Module.rank ℝ E
s : Set E
hs : s.Countable
this : Nontrivial E
a : E
ha : a ∈ sᶜ
b : E
hb : b ∈ sᶜ
hab : a ≠ b
c : E := 2⁻¹ • (a + b)
x : E := 2⁻¹ • (b - a)
Ia : c - x = a
Ib : c + x = b
x_ne_zero : x ≠ 0
y : E
hy : LinearIndependent ℝ ![x, y]
A : {t | ([c + x -[ℝ] c + t • y] ∩ s).Nonempty}.Countable
B : {t | ([c - x -[ℝ] c + t • y] ∩ s).Nonempty}.Countable
t : ℝ
z : E := c + t • y
ht : [c + x -[ℝ] c + t • y] ∩ s = ∅ ∧ [c - x -[ℝ] c + t • y] ∩ s = ∅
JA : JoinedIn sᶜ a z
⊢ JoinedIn sᶜ b z

Tactic:
apply JoinedIn.of_segment_subset

Goal state after:
E : Type u_1
inst✝⁴ : AddCommGroup E
inst✝³ : Module ℝ E
inst✝² : TopologicalSpace E
inst✝¹ : ContinuousAdd E
inst✝ : ContinuousSMul ℝ E
h : 1 < Module.rank ℝ E
s : Set E
hs : s.Countable
this : Nontrivial E
a : E
ha : a ∈ sᶜ
b : E
hb : b ∈ sᶜ
hab : a ≠ b
c : E := ⋯
x : E := ⋯
Ia : c - x = a
Ib : c + x = b
x_ne_zero : x ≠ 0
y : E
hy : LinearIndependent ℝ ![x, y]
A : {t | ([c + x -[ℝ] c + t • y] ∩ s).Nonempty}.Countable
B : {t | ([c - x -[ℝ] c + t • y] ∩ s).Nonempty}.Countable
t : ℝ
z : E := ⋯
ht : [c + x -[ℝ] c + t • y] ∩ s = ∅ ∧ [c - x -[ℝ] c + t • y] ∩ s = ∅
JA : JoinedIn sᶜ a z
⊢ [b -[ℝ] z] ⊆ sᶜ
Module: Mathlib.Analysis.Calculus.InverseFunctionTheorem.Analytic

Goal state before:
pp: 𝕜 : Type u_1
inst✝⁴ : NontriviallyNormedField 𝕜
f : 𝕜 → 𝕜
x : 𝕜
inst✝³ : CompleteSpace 𝕜
inst✝² : CharZero 𝕜
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
g : 𝕜 → E
hf : AnalyticAt 𝕜 f x
hf' : deriv f x ≠ 0
⊢ AnalyticAt 𝕜 (g ∘ f) x ↔ AnalyticAt 𝕜 g (f x)

Tactic:
refine ⟨fun hg ↦ ?_, (AnalyticAt.comp · hf)⟩
  let r := hf.hasStrictDerivAt.localInverse _ _ _ hf'
  have hra : AnalyticAt 𝕜 r (f x) := hf.analyticAt_localInverse hf'
  have : r (f x) = x := HasStrictFDerivAt.localInverse_apply_image ..
  rw [← this] at hg
  exact (hg.comp hra).congr <| .fun_comp (HasStrictDerivAt.eventually_right_inverse ..) g

Goal state after: