mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.Topology.Maps.Proper.Basic

Goal state before:
pp: case mpr
X : Type u_1
Y : Type u_2
inst✝¹ : TopologicalSpace X
inst✝ : TopologicalSpace Y
f : X → Y
x✝ : Continuous[inst✝¹, inst✝] f
H : ∀ ⦃𝒰 : Ultrafilter X⦄ ⦃y : Y⦄, Tendsto f (↑𝒰) (𝓝 y) → ∃ x, f x = y ∧ ↑𝒰 ≤ 𝓝 x
⊢ ∀ ⦃ℱ : Filter X⦄ ⦃y : Y⦄, (∃ u, ↑u ≤ comap f (𝓝 y) ⊓ ℱ) → ∃ x, f x = y ∧ ∃ u, ↑u ≤ 𝓝 x ⊓ ℱ

Tactic:
forall_exists_index

Goal state after:
case mpr
X : Type u_1
Y : Type u_2
inst✝¹ : TopologicalSpace X
inst✝ : TopologicalSpace Y
f : X → Y
x✝ : Continuous[inst✝¹, inst✝] f
H : ∀ ⦃𝒰 : Ultrafilter X⦄ ⦃y : Y⦄, Tendsto f (↑𝒰) (𝓝 y) → ∃ x, f x = y ∧ ↑𝒰 ≤ 𝓝 x
⊢ ∀ ⦃ℱ : Filter X⦄ ⦃y : Y⦄ (x : Ultrafilter X), ↑x ≤ comap f (𝓝 y) ⊓ ℱ → ∃ x, f x = y ∧ ∃ u, ↑u ≤ 𝓝 x ⊓ ℱ
Module: Mathlib.Topology.Algebra.Monoid

Goal state before:
pp: ι : Type u_1
M : Type u_3
X : Type u_5
inst✝³ : TopologicalSpace X
inst✝² : TopologicalSpace M
inst✝¹ : Monoid M
inst✝ : ContinuousMul M
f : ι → X → M
l : List ι
t : Set X
h : ∀ i ∈ l, ContinuousOn (f i) t
x : X
hx : x ∈ t
⊢ ContinuousWithinAt (fun a ↦ (List.map (fun i ↦ f i a) l).prod) t x

Tactic:
continuousWithinAt_iff_continuousAt_domRestrict _ hx

Goal state after:
ι : Type u_1
M : Type u_3
X : Type u_5
inst✝³ : TopologicalSpace X
inst✝² : TopologicalSpace M
inst✝¹ : Monoid M
inst✝ : ContinuousMul M
f : ι → X → M
l : List ι
t : Set X
h : ∀ i ∈ l, ContinuousOn (f i) t
x : X
hx : x ∈ t
⊢ ContinuousAt (t.domRestrict fun a ↦ (List.map (fun i ↦ f i a) l).prod) ⟨x, hx⟩
Module: Mathlib.Topology.Algebra.Monoid

Goal state before:
pp: ι : Type u_1
M : Type u_3
X : Type u_5
inst✝³ : TopologicalSpace X
inst✝² : TopologicalSpace M
inst✝¹ : Monoid M
inst✝ : ContinuousMul M
f : ι → X → M
l : List ι
t : Set X
x : X
hx : x ∈ t
i : ι
h : ContinuousWithinAt (f i) t x
hi : i ∈ l
⊢ Tendsto (fun b ↦ f i ↑b) (𝓝 ⟨x, hx⟩) (𝓝 (f i ↑⟨x, hx⟩))

Tactic:
continuousWithinAt_iff_continuousAt_domRestrict _ hx

Goal state after:
ι : Type u_1
M : Type u_3
X : Type u_5
inst✝³ : TopologicalSpace X
inst✝² : TopologicalSpace M
inst✝¹ : Monoid M
inst✝ : ContinuousMul M
f : ι → X → M
l : List ι
t : Set X
x : X
hx : x ∈ t
i : ι
h : ContinuousAt (t.domRestrict (f i)) ⟨x, hx⟩
hi : i ∈ l
⊢ Tendsto (fun b ↦ f i ↑b) (𝓝 ⟨x, hx⟩) (𝓝 (f i ↑⟨x, hx⟩))
Module: Mathlib.Topology.Algebra.Group.Pointwise

Goal state before:
pp: G : Type w
inst✝² : TopologicalSpace G
inst✝¹ : Group G
inst✝ : IsTopologicalGroup G
s : Set G
hs : IsOpen[inst✝²] s
t : Set G
⊢ s / closure[inst✝²] t = s / t

Tactic:
by
  simp_rw [div_eq_mul_inv, inv_closure, hs.mul_closure]

Goal state after:
Module: Mathlib.Topology.Algebra.IsUniformGroup.Defs

Goal state before:
pp: α : Type u_1
β : Type u_2
inst✝³ : UniformSpace α
inst✝² : Group α
inst✝¹ : IsUniformGroup α
inst✝ : UniformSpace β
f : β → α
hf : UniformContinuous f
n : ℕ
⊢ UniformContinuous fun x ↦ f x ^ ↑n

Tactic:
simp_rw [zpow_natCast]

Goal state after:
α : Type u_1
β : Type u_2
inst✝³ : UniformSpace α
inst✝² : Group α
inst✝¹ : IsUniformGroup α
inst✝ : UniformSpace β
f : β → α
hf : UniformContinuous f
n : ℕ
⊢ UniformContinuous fun x ↦ f x ^ n
Module: Mathlib.Topology.Algebra.Group.Basic

Goal state before:
pp: G : Type u_1
inst✝² : TopologicalSpace G
inst✝¹ : MulOneClass G
inst✝ : ContinuousMul G
g h : G
hg : g ∈ connectedComponent 1
hh : h ∈ connectedComponent 1
⊢ (fun x ↦ g * x) 1 = g

Tactic:
simp only [mul_one]

Goal state after:
Module: Mathlib.Topology.Algebra.Group.Pointwise

Goal state before:
pp: G : Type w
inst✝² : TopologicalSpace G
inst✝¹ : Group G
inst✝ : IsTopologicalGroup G
S : Subgroup G
hS : IsDiscrete ↑S
V : Set G
hV : V ∈ 𝓝 1 ∧ V ∩ ↑S = {1}
U : Set G
hU : U ∈ 𝓝 1
hUinv : U⁻¹ = U
hUV : U * U ⊆ V
g : G
hgS : g ∈ S
x : G
hx : x ∈ U⁻¹
hgx : (fun x ↦ g * x) x ∈ U
⊢ g ∈ U * U

Tactic:
exact ⟨_, hgx, _, hx, by simp⟩

Goal state after:
Module: Mathlib.Topology.Algebra.IsUniformGroup.Defs

Goal state before:
pp: β : Type u_2
inst✝³ : UniformSpace β
inst✝² : Group β
inst✝¹ : IsLeftUniformGroup β
inst✝ : IsRightUniformGroup β
dr : β × β → β := fun xy ↦ xy.2 * xy.1⁻¹
dl : β × β → β := fun xy ↦ xy.1⁻¹ * xy.2
conj : β × β → β := fun gx ↦ gx.1 * gx.2 * gx.1⁻¹
⊢ comap (fun gx ↦ gx.1 * gx.2 * gx.1⁻¹) (𝓝 1) = comap snd (𝓝 1)

Tactic:
let φ : β × β ≃ β × β := (Equiv.refl β).prodShear (fun b ↦ (Equiv.mulLeft b).symm)

Goal state after:
β : Type u_2
inst✝³ : UniformSpace β
inst✝² : Group β
inst✝¹ : IsLeftUniformGroup β
inst✝ : IsRightUniformGroup β
dr : β × β → β := fun xy ↦ xy.2 * xy.1⁻¹
dl : β × β → β := fun xy ↦ xy.1⁻¹ * xy.2
conj : β × β → β := fun gx ↦ gx.1 * gx.2 * gx.1⁻¹
φ : β × β ≃ β × β := (Equiv.refl β).prodShear fun b ↦ Equiv.symm (Equiv.mulLeft b)
⊢ comap (fun gx ↦ gx.1 * gx.2 * gx.1⁻¹) (𝓝 1) = comap snd (𝓝 1)
Module: Mathlib.Topology.Algebra.Group.Basic

Goal state before:
pp: G : Type w
inst✝⁴ : Group G
inst✝³ : TopologicalSpace G
inst✝² : IsTopologicalGroup G
α : Type u_1
l : Filter α
inst✝¹ : l.NeBot
inst✝ : T2Space G
f g : α → G
a : G
hf : Tendsto f l (𝓝 a)
hg : Tendsto g l (𝓝 a)
⊢ Tendsto (fun x ↦ f x / g x) l (𝓝 1)

Tactic:
simpa using hf.div' hg

Goal state after:
Module: Mathlib.Topology.Algebra.IsUniformGroup.Defs

Goal state before:
pp: α : Type u_1
β : Type u_2
inst✝⁷ : UniformSpace α
inst✝⁶ : Group α
inst✝⁵ : IsUniformGroup α
hom : Type u_3
inst✝⁴ : UniformSpace β
inst✝³ : Group β
inst✝² : IsUniformGroup β
inst✝¹ : FunLike hom α β
inst✝ : MonoidHomClass hom α β
f : hom
h : Tendsto (⇑f) (𝓝 1) (𝓝 1)
x✝ : α × α
⊢ ((fun x ↦ x.2 / x.1) ∘ fun x ↦ (f x.1, f x.2)) x✝ = f (x✝.2 / x✝.1)

Tactic:
simp only [Function.comp_apply, map_div]

Goal state after:
Module: Mathlib.Topology.Algebra.IsUniformGroup.Basic

Goal state before:
pp: G : Type u_1
inst✝² : Group G
inst✝¹ : TopologicalSpace G
inst✝ : IsTopologicalGroup G
⊢ UniformSpace.comap op (IsTopologicalGroup.rightUniformSpace Gᵐᵒᵖ) = IsTopologicalGroup.leftUniformSpace G

Tactic:
by
  ext : 1
  change comap (fun (x : G × G) ↦ (MulOpposite.op x.1, MulOpposite.op x.2))
      (comap (fun p : Gᵐᵒᵖ × Gᵐᵒᵖ => p.2 * p.1⁻¹) (𝓝 1))
    = comap (fun p : G × G => p.1⁻¹ * p.2) (𝓝 1)
  have : 𝓝 (1 : G) = comap (MulOpposite.opHomeomorph) (𝓝 (1 : Gᵐᵒᵖ)) := by
    simp [Homeomorph.comap_nhds_eq]
  simp_rw [comap_comap, this, comap_comap]
  rfl

Goal state after:
Module: Mathlib.Topology.Algebra.Field

Goal state before:
pp: K : Type u_2
inst✝⁴ : DivisionRing K
inst✝³ : TopologicalSpace K
inst✝² : IsTopologicalRing K
inst✝¹ : CompactSpace K
inst✝ : T2Space K
⊢ Finite K

Tactic:
by
  suffices DiscreteTopology K by
    exact finite_of_compact_of_discrete
  rw [discreteTopology_iff_isOpen_singleton_zero]
  exact GroupWithZero.isOpen_singleton_zero

Goal state after:
Module: Mathlib.Order.Interval.Set.Pi

Goal state before:
pp: ι : Type u_1
α : ι → Type u_2
inst✝¹ : (i : ι) → Preorder (α i)
inst✝ : DecidableEq ι
x y : (i : ι) → α i
i₀ : ι
m : α i₀
hm : m ≤ y i₀
⊢ (univ.pi fun i ↦ Ioc (x i) (update y i₀ m i)) = {z | z i₀ ≤ m} ∩ univ.pi fun i ↦ Ioc (x i) (y i)

Tactic:
by
  have : Ioc (x i₀) m = Iic m ∩ Ioc (x i₀) (y i₀) := by
    rw [← Ioi_inter_Iic, ← Ioi_inter_Iic, inter_left_comm,
      inter_eq_self_of_subset_left (Iic_subset_Iic.2 hm)]
  simp_rw [univ_pi_update i₀ y m fun i z ↦ Ioc (x i) z, ← pi_inter_compl ({i₀} : Set ι),
    singleton_pi', ← inter_assoc, this]
  rfl

Goal state after:
Module: Mathlib.Topology.Algebra.Order.Field

Goal state before:
pp: 𝕜 : Type u_1
inst✝⁴ : Semifield 𝕜
inst✝³ : LinearOrder 𝕜
inst✝² : IsStrictOrderedRing 𝕜
inst✝¹ : TopologicalSpace 𝕜
inst✝ : OrderTopology 𝕜
n : ℤ
hn : 0 < -n
N : ℕ
h : ↑N = -n
⊢ Tendsto (fun x ↦ x ^ n) atTop (𝓝 0)

Tactic:
← h,

Goal state after:
𝕜 : Type u_1
inst✝⁴ : Semifield 𝕜
inst✝³ : LinearOrder 𝕜
inst✝² : IsStrictOrderedRing 𝕜
inst✝¹ : TopologicalSpace 𝕜
inst✝ : OrderTopology 𝕜
n : ℤ
N : ℕ
hn : 0 < ↑N
h : ↑N = -n
⊢ Tendsto (fun x ↦ x ^ n) atTop (𝓝 0)
Module: Mathlib.Topology.Algebra.Order.Field

Goal state before:
pp: 𝕜 : Type u_1
inst✝⁴ : Field 𝕜
inst✝³ : LinearOrder 𝕜
inst✝² : IsStrictOrderedRing 𝕜
inst✝¹ : TopologicalSpace 𝕜
inst✝ : OrderTopology 𝕜
n : ℕ
c d : 𝕜
⊢ Tendsto (fun x ↦ c * x ^ n) atTop (𝓝 d) ↔ (c = 0 ∨ n = 0) ∧ c = d

Tactic:
rcases eq_or_ne n 0 with (rfl | hn)

Goal state after:
case inl
𝕜 : Type u_1
inst✝⁴ : Field 𝕜
inst✝³ : LinearOrder 𝕜
inst✝² : IsStrictOrderedRing 𝕜
inst✝¹ : TopologicalSpace 𝕜
inst✝ : OrderTopology 𝕜
c d : 𝕜
⊢ Tendsto (fun x ↦ c * x ^ 0) atTop (𝓝 d) ↔ (c = 0 ∨ 0 = 0) ∧ c = d

case inr
𝕜 : Type u_1
inst✝⁴ : Field 𝕜
inst✝³ : LinearOrder 𝕜
inst✝² : IsStrictOrderedRing 𝕜
inst✝¹ : TopologicalSpace 𝕜
inst✝ : OrderTopology 𝕜
n : ℕ
c d : 𝕜
hn : n ≠ 0
⊢ Tendsto (fun x ↦ c * x ^ n) atTop (𝓝 d) ↔ (c = 0 ∨ n = 0) ∧ c = d
Module: Mathlib.Topology.Order.Basic

Goal state before:
pp: α : Type u
β : Type v
γ : Type w
ts : TopologicalSpace α
inst✝² : Preorder α
inst✝¹ : OrderTopology α
inst✝ : Countable α
⊢ SecondCountableTopology α

Tactic:
refine ⟨{ s : Set α | ∃ a, s = Ioi a ∨ s = Iio a }, ?_, ?_⟩

Goal state after:
case refine_1
α : Type u
β : Type v
γ : Type w
ts : TopologicalSpace α
inst✝² : Preorder α
inst✝¹ : OrderTopology α
inst✝ : Countable α
⊢ {s | ∃ a, s = Ioi a ∨ s = Iio a}.Countable

case refine_2
α : Type u
β : Type v
γ : Type w
ts : TopologicalSpace α
inst✝² : Preorder α
inst✝¹ : OrderTopology α
inst✝ : Countable α
⊢ ts = generateFrom {s | ∃ a, s = Ioi a ∨ s = Iio a}
Module: Mathlib.Topology.Order.Basic

Goal state before:
pp: α : Type u
ts : TopologicalSpace α
inst✝¹ : Preorder α
inst✝ : OrderTopology α
a : α
⊢ 𝓝 a = (⨅ b ∈ Iio a, 𝓟 (Ioi b)) ⊓ ⨅ b ∈ Ioi a, 𝓟 (Iio b)

Tactic:
OrderTopology.topology_eq_generate_intervals (α := α),

Goal state after:
α : Type u
ts : TopologicalSpace α
inst✝¹ : Preorder α
inst✝ : OrderTopology α
a : α
⊢ 𝓝 a = (⨅ b ∈ Iio a, 𝓟 (Ioi b)) ⊓ ⨅ b ∈ Ioi a, 𝓟 (Iio b)
Module: Mathlib.Algebra.Module.CharacterModule

Goal state before:
pp: A : Type uA
inst✝ : AddCommGroup A
a : A
h : a ≠ 0
⊢ ∃ c, c a ≠ 0

Tactic:
exact exists_character_apply_ne_zero_of_ne_zero h

Goal state after:
Module: Mathlib.Topology.Instances.AddCircle.Defs

Goal state before:
pp: 𝕜 : Type u_1
inst✝³ : AddCommGroup 𝕜
p : 𝕜
inst✝² : LinearOrder 𝕜
inst✝¹ : IsOrderedAddMonoid 𝕜
hp : Fact (0 < p)
inst✝ : Archimedean 𝕜
α : Type u_3
f g : AddCircle p → α
a : 𝕜
h : ∀ x ∈ Ico a (a + p), f ↑x = g ↑x
⊢ f = g

Tactic:
by
  rw [← Set.eqOn_univ, ← coe_image_Ico_eq p a]
  rintro - ⟨x, hx, rfl⟩
  exact h x hx

Goal state after:
Module: Mathlib.Topology.Order.Basic

Goal state before:
pp: case a
X : Type u_1
inst✝⁵ : ConditionallyCompleteLinearOrder X
inst✝⁴ : TopologicalSpace X
inst✝³ : OrderTopology X
Y : Type u_2
inst✝² : ConditionallyCompleteLinearOrder Y
inst✝¹ : TopologicalSpace Y
inst✝ : OrderTopology Y
f : X → Y
x : X
hf : LeftOrdContinuous f
z : Y
hxz : f x ∈ Ioi z
ne : (f ⁻¹' Iic z).Nonempty
bdd : BddAbove (f ⁻¹' Iic z)
a : X
ha : a ∈ f ⁻¹' Ioi z
this : sSup (f '' f ⁻¹' Iic z) ≤ z
⊢ sSup (f ⁻¹' Iic z) ≠ a

Tactic:
exact fun h ↦ this.not_gt ((h ▸ ha).trans_eq (hf.map_csSup ne bdd))

Goal state after:
Module: Mathlib.Topology.Instances.AddCircle.Defs

Goal state before:
pp: case refine_1
𝕜 : Type u_1
B : Type u_2
inst✝² : Field 𝕜
p q : 𝕜
inst✝¹ : LinearOrder 𝕜
inst✝ : IsStrictOrderedRing 𝕜
hp : Fact (0 < p)
n : ℕ
hn : 0 < n
m₁ m₂ : ↑{m | m < n ∧ m.gcd n = 1}
h : ↑m₁ • ↑(p / ↑n) = ↑m₂ • ↑(p / ↑n)
⊢ ↑m₁ = ↑m₂

Tactic:
refine nsmul_injOn_Iio_addOrderOf ?_ ?_ h

Goal state after:
case refine_1.refine_1
𝕜 : Type u_1
B : Type u_2
inst✝² : Field 𝕜
p q : 𝕜
inst✝¹ : LinearOrder 𝕜
inst✝ : IsStrictOrderedRing 𝕜
hp : Fact (0 < p)
n : ℕ
hn : 0 < n
m₁ m₂ : ↑{m | m < n ∧ m.gcd n = 1}
h : ↑m₁ • ↑(p / ↑n) = ↑m₂ • ↑(p / ↑n)
⊢ ↑m₁ ∈ Iio (addOrderOf ↑(p / ↑n))

case refine_1.refine_2
𝕜 : Type u_1
B : Type u_2
inst✝² : Field 𝕜
p q : 𝕜
inst✝¹ : LinearOrder 𝕜
inst✝ : IsStrictOrderedRing 𝕜
hp : Fact (0 < p)
n : ℕ
hn : 0 < n
m₁ m₂ : ↑{m | m < n ∧ m.gcd n = 1}
h : ↑m₁ • ↑(p / ↑n) = ↑m₂ • ↑(p / ↑n)
⊢ ↑m₂ ∈ Iio (addOrderOf ↑(p / ↑n))
Module: Mathlib.Algebra.Category.ModuleCat.Subobject

Goal state before:
pp: case i
R : Type u
inst✝ : Ring R
M : ModuleCat R
S : Subobject M
⊢ underlying.obj S ≅ of R ↥((fun S ↦ (Hom.hom S.arrow).range) S)

pp: case w
R : Type u
inst✝ : Ring R
M : ModuleCat R
S : Subobject M
⊢ Iso.hom ?i ≫ ↟((fun S ↦ (Hom.hom S.arrow).range) S).subtype = S.arrow

Tactic:
· apply LinearEquiv.toModuleIso
          apply LinearEquiv.ofBijective (LinearMap.codRestrict
            (LinearMap.range S.arrow.hom) S.arrow.hom _)
          constructor
          · simp [← LinearMap.ker_eq_bot, ker_eq_bot_of_mono]
          · rw [← LinearMap.range_eq_top, LinearMap.range_codRestrict,
              Submodule.comap_subtype_self]
            exact LinearMap.mem_range_self _

Goal state after:
case w
R : Type u
inst✝ : Ring R
M : ModuleCat R
S : Subobject M
⊢ (LinearEquiv.ofBijective (LinearMap.codRestrict (Hom.hom S.arrow).range (Hom.hom S.arrow) ⋯) ⋯).toModuleIso.hom ≫
      ↟((fun S ↦ (Hom.hom S.arrow).range) S).subtype =
    S.arrow
Module: Mathlib.Algebra.Homology.ExactSequence

Goal state before:
pp: case mpr.refine_1
C : Type u_1
inst✝¹ : Category.{v_1, u_1} C
inst✝ : HasZeroMorphisms C
n : ℕ
S : ComposableArrows C (n + 2)
h : S.δlast.Exact
h' : (mk₂ (S.map' n (n + 1) ⋯ ⋯) (S.map' (n + 1) (n + 2) ⋯ ⋯)).Exact
i : ℕ
hi : i + 2 ≤ n + 2
⊢ S.map' i (i + 1) ⋯ ⋯ ≫ S.map' (i + 1) (i + 2) ⋯ hi = 0

Tactic:
simp only [Nat.add_le_add_iff_right] at hi

Goal state after:
case mpr.refine_1
C : Type u_1
inst✝¹ : Category.{v_1, u_1} C
inst✝ : HasZeroMorphisms C
n : ℕ
S : ComposableArrows C (n + 2)
h : S.δlast.Exact
h' : (mk₂ (S.map' n (n + 1) ⋯ ⋯) (S.map' (n + 1) (n + 2) ⋯ ⋯)).Exact
i : ℕ
hi✝ : i + 2 ≤ n + 2
hi : i ≤ n
⊢ S.map' i (i + 1) ⋯ ⋯ ≫ S.map' (i + 1) (i + 2) ⋯ hi✝ = 0
Module: Mathlib.Algebra.Homology.ExactSequence

Goal state before:
pp: case mpr.refine_2
C : Type u_1
inst✝¹ : Category.{v_1, u_1} C
inst✝ : HasZeroMorphisms C
n : ℕ
S : ComposableArrows C (n + 2)
h : S.δlast.Exact
h' : (mk₂ (S.map' n (n + 1) ⋯ ⋯) (S.map' (n + 1) (n + 2) ⋯ ⋯)).Exact
i : ℕ
hi : i + 2 ≤ n + 2
⊢ (S.sc ⋯ i hi).Exact

Tactic:
simp only [Nat.add_le_add_iff_right] at hi

Goal state after:
case mpr.refine_2
C : Type u_1
inst✝¹ : Category.{v_1, u_1} C
inst✝ : HasZeroMorphisms C
n : ℕ
S : ComposableArrows C (n + 2)
h : S.δlast.Exact
h' : (mk₂ (S.map' n (n + 1) ⋯ ⋯) (S.map' (n + 1) (n + 2) ⋯ ⋯)).Exact
i : ℕ
hi✝ : i + 2 ≤ n + 2
hi : i ≤ n
⊢ (S.sc ⋯ i hi✝).Exact
Module: Mathlib.Algebra.Homology.ShortComplex.SnakeLemma

Goal state before:
pp: C : Type u_1
inst✝¹ : Category.{v_1, u_1} C
inst✝ : Abelian C
S : SnakeInput C
A : C
x₂ : A ⟶ S.L₀.X₂
hx₂ : x₂ ≫ S.L₀.g = 0
⊢ ∃ A' π, ∃ (_ : Epi π), ∃ x₁, π ≫ x₂ = x₁ ≫ S.L₀.f

Tactic:
obtain ⟨A₁, π₁, hπ₁, y₁, hy₁⟩ := S.L₁_exact.exact_up_to_refinements (x₂ ≫ S.v₀₁.τ₂)
    (by rw [assoc, S.v₀₁.comm₂₃, reassoc_of% hx₂, zero_comp])

Goal state after:
C : Type u_1
inst✝¹ : Category.{v_1, u_1} C
inst✝ : Abelian C
S : SnakeInput C
A : C
x₂ : A ⟶ S.L₀.X₂
hx₂ : x₂ ≫ S.L₀.g = 0
A₁ : C
π₁ : A₁ ⟶ A
hπ₁ : Epi π₁
y₁ : A₁ ⟶ S.L₁.X₁
hy₁ : π₁ ≫ x₂ ≫ S.v₀₁.τ₂ = y₁ ≫ S.L₁.f
⊢ ∃ A' π, ∃ (_ : Epi π), ∃ x₁, π ≫ x₂ = x₁ ≫ S.L₀.f
Module: Mathlib.Algebra.Homology.ShortComplex.SnakeLemma

Goal state before:
pp: C : Type u_1
inst✝¹ : Category.{v_1, u_1} C
inst✝ : Abelian C
S S₁ S₂ S₃ : SnakeInput C
f : S₁.Hom S₂
g : S₂.Hom S₃
⊢ (f.f₁ ≫ g.f₁) ≫ S₃.v₁₂ = S₁.v₁₂ ≫ f.f₂ ≫ g.f₂

Tactic:
by simp only [assoc, comm₁₂, comm₁₂_assoc]

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

Goal state before:
pp: C : Type u_1
inst✝¹ : Category.{v_1, u_1} C
inst✝ : Abelian C
S₁ S₂ : SnakeInput C
f : S₁ ⟶ S₂
⊢ functorP.map f ≫ S₂.φ₁ ≫ S₂.v₂₃.τ₁ = pullback.snd S₁.L₁.g S₁.v₀₁.τ₃ ≫ f.f₀.τ₃ ≫ S₂.δ

Tactic:
← S₂.snd_δ,

Goal state after:
C : Type u_1
inst✝¹ : Category.{v_1, u_1} C
inst✝ : Abelian C
S₁ S₂ : SnakeInput C
f : S₁ ⟶ S₂
⊢ functorP.map f ≫ pullback.snd S₂.L₁.g S₂.v₀₁.τ₃ ≫ S₂.δ = pullback.snd S₁.L₁.g S₁.v₀₁.τ₃ ≫ f.f₀.τ₃ ≫ S₂.δ
Module: Mathlib.CategoryTheory.Limits.Shapes.Multiequalizer

Goal state before:
pp: J : MulticospanShape
C : Type u_1
inst✝ : Category.{v_1, u_1} C
F G : WalkingMulticospan J ⥤ C
left : ∀ (i : J.L), F.obj (WalkingMulticospan.left i) = G.obj (WalkingMulticospan.left i)
right : ∀ (i : J.R), F.obj (WalkingMulticospan.right i) = G.obj (WalkingMulticospan.right i)
wl : ∀ (i : J.R), F.map (Hom.fst i) ≫ eqToHom ⋯ = eqToHom ⋯ ≫ G.map (Hom.fst i)
wr : ∀ (i : J.R), F.map (Hom.snd i) ≫ eqToHom ⋯ = eqToHom ⋯ ≫ G.map (Hom.snd i)
⊢ ∀ (X : WalkingMulticospan J), (functorExt (fun x ↦ eqToIso ⋯) (fun x ↦ eqToIso ⋯) wl wr).hom.app X = eqToHom ⋯

Tactic:
rintro (_ | _) <;> simp

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

Goal state before:
pp: C : Type u
inst✝ : Category.{v, u} C
J : MulticospanShape
I : MulticospanIndex J C
c : Fan I.left
hc : IsLimit c
d : Fan I.right
hd : IsLimit d
K₁ K₂ : Fork (I.fstPiMapOfIsLimit c hd) (I.sndPiMapOfIsLimit c hd)
f : K₁ ⟶ K₂
⊢ ∀ (j : WalkingMulticospan J), f.hom ≫ (Multifork.ofPiFork K₂).π.app j = (Multifork.ofPiFork K₁).π.app j

Tactic:
rintro (_ | _) <;> simp

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

Goal state before:
pp: C : Type u
inst✝ : Category.{v, u} C
J : MulticospanShape
I : MulticospanIndex J C
c : Fan I.left
hc : IsLimit c
d : Fan I.right
hd : IsLimit d
K : Multifork I
⊢ ∀ (j : WalkingMulticospan J),
    ((𝟭 (Multifork I)).obj K).π.app j =
      (Iso.refl ((𝟭 (Multifork I)).obj K).pt).hom ≫ ((I.toPiForkFunctor hc hd ⋙ I.ofPiForkFunctor hd).obj K).π.app j

Tactic:
rintro (_ | _) <;> simp

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

Goal state before:
pp: C : Type u
inst✝ : Category.{v, u} C
J : MultispanShape
I : MultispanIndex J C
c : Cofan I.left
hc : IsColimit c
d : Cofan I.right
hd : IsColimit d
K₁ K₂ : Cofork (I.fstSigmaMapOfIsColimit d hc) (I.sndSigmaMapOfIsColimit d hc)
f : K₁ ⟶ K₂
⊢ ∀ (j : WalkingMultispan J), (Multicofork.ofSigmaCofork K₁).ι.app j ≫ f.hom = (Multicofork.ofSigmaCofork K₂).ι.app j

Tactic:
rintro (_ | _) <;> simp

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

Goal state before:
pp: C : Type u
inst✝ : Category.{v, u} C
J : MultispanShape
I : MultispanIndex J C
c : Cofan I.left
hc : IsColimit c
d : Cofan I.right
hd : IsColimit d
K : Multicofork I
⊢ ∀ (j : WalkingMultispan J),
    ((𝟭 (Multicofork I)).obj K).ι.app j ≫ (Iso.refl ((𝟭 (Multicofork I)).obj K).pt).hom =
      ((I.toSigmaCoforkFunctor hc hd ⋙ I.ofSigmaCoforkFunctor hc).obj K).ι.app j

Tactic:
rintro (_ | _) <;> simp

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

Goal state before:
pp: case left.reflexion
C : Type u
inst✝ : Category.{v, u} C
A B : C
f g : A ⟶ B
s : B ⟶ A
sl : s ≫ f = 𝟙 B
sr : s ≫ g = 𝟙 B
⊢ (match one, one, Hom.left ≫ Hom.reflexion with
    | x, .(x), Hom.id .(x) =>
      𝟙
        (match x with
        | zero => B
        | one => A)
    | .(one), .(zero), Hom.left => f
    | .(one), .(zero), Hom.right => g
    | .(zero), .(one), Hom.reflexion => s
    | .(one), .(one), Hom.rightCompReflexion => g ≫ s
    | .(one), .(one), Hom.leftCompReflexion => f ≫ s) =
    (match one, zero, Hom.left with
      | x, .(x), Hom.id .(x) =>
        𝟙
          (match x with
          | zero => B
          | one => A)
      | .(one), .(zero), Hom.left => f
      | .(one), .(zero), Hom.right => g
      | .(zero), .(one), Hom.reflexion => s
      | .(one), .(one), Hom.rightCompReflexion => g ≫ s
      | .(one), .(one), Hom.leftCompReflexion => f ≫ s) ≫
      match zero, one, Hom.reflexion with
      | x, .(x), Hom.id .(x) =>
        𝟙
          (match x with
          | zero => B
          | one => A)
      | .(one), .(zero), Hom.left => f
      | .(one), .(zero), Hom.right => g
      | .(zero), .(one), Hom.reflexion => s
      | .(one), .(one), Hom.rightCompReflexion => g ≫ s
      | .(one), .(one), Hom.leftCompReflexion => f ≫ s

Tactic:
simp only [Category.id_comp, Category.comp_id, Category.assoc, sl, sr,
        reassoc_of% sl, reassoc_of% sr]

Goal state after:
case left.reflexion
C : Type u
inst✝ : Category.{v, u} C
A B : C
f g : A ⟶ B
s : B ⟶ A
sl : s ≫ f = 𝟙 B
sr : s ≫ g = 𝟙 B
⊢ (match one, one, Hom.left ≫ Hom.reflexion with
    | x, .(x), Hom.id .(x) =>
      𝟙
        (match x with
        | zero => B
        | one => A)
    | .(one), .(zero), Hom.left => f
    | .(one), .(zero), Hom.right => g
    | .(zero), .(one), Hom.reflexion => s
    | .(one), .(one), Hom.rightCompReflexion => g ≫ s
    | .(one), .(one), Hom.leftCompReflexion => f ≫ s) =
    f ≫ s
Module: Mathlib.CategoryTheory.Limits.Shapes.Reflexive

Goal state before:
pp: case left.id
C : Type u
inst✝ : Category.{v, u} C
A B : C
f g : A ⟶ B
s : B ⟶ A
sl : s ≫ f = 𝟙 B
sr : s ≫ g = 𝟙 B
⊢ (match one, zero, Hom.left ≫ Hom.id zero with
    | x, .(x), Hom.id .(x) =>
      𝟙
        (match x with
        | zero => B
        | one => A)
    | .(one), .(zero), Hom.left => f
    | .(one), .(zero), Hom.right => g
    | .(zero), .(one), Hom.reflexion => s
    | .(one), .(one), Hom.rightCompReflexion => g ≫ s
    | .(one), .(one), Hom.leftCompReflexion => f ≫ s) =
    (match one, zero, Hom.left with
      | x, .(x), Hom.id .(x) =>
        𝟙
          (match x with
          | zero => B
          | one => A)
      | .(one), .(zero), Hom.left => f
      | .(one), .(zero), Hom.right => g
      | .(zero), .(one), Hom.reflexion => s
      | .(one), .(one), Hom.rightCompReflexion => g ≫ s
      | .(one), .(one), Hom.leftCompReflexion => f ≫ s) ≫
      match zero, zero, Hom.id zero with
      | x, .(x), Hom.id .(x) =>
        𝟙
          (match x with
          | zero => B
          | one => A)
      | .(one), .(zero), Hom.left => f
      | .(one), .(zero), Hom.right => g
      | .(zero), .(one), Hom.reflexion => s
      | .(one), .(one), Hom.rightCompReflexion => g ≫ s
      | .(one), .(one), Hom.leftCompReflexion => f ≫ s

Tactic:
simp only [Category.id_comp, Category.comp_id, Category.assoc, sl, sr,
        reassoc_of% sl, reassoc_of% sr]

Goal state after:
case left.id
C : Type u
inst✝ : Category.{v, u} C
A B : C
f g : A ⟶ B
s : B ⟶ A
sl : s ≫ f = 𝟙 B
sr : s ≫ g = 𝟙 B
⊢ (match one, zero, Hom.left ≫ Hom.id zero with
    | x, .(x), Hom.id .(x) =>
      𝟙
        (match x with
        | zero => B
        | one => A)
    | .(one), .(zero), Hom.left => f
    | .(one), .(zero), Hom.right => g
    | .(zero), .(one), Hom.reflexion => s
    | .(one), .(one), Hom.rightCompReflexion => g ≫ s
    | .(one), .(one), Hom.leftCompReflexion => f ≫ s) =
    f
Module: Mathlib.CategoryTheory.Limits.Shapes.Reflexive

Goal state before:
pp: case right.reflexion
C : Type u
inst✝ : Category.{v, u} C
A B : C
f g : A ⟶ B
s : B ⟶ A
sl : s ≫ f = 𝟙 B
sr : s ≫ g = 𝟙 B
⊢ (match one, one, Hom.right ≫ Hom.reflexion with
    | x, .(x), Hom.id .(x) =>
      𝟙
        (match x with
        | zero => B
        | one => A)
    | .(one), .(zero), Hom.left => f
    | .(one), .(zero), Hom.right => g
    | .(zero), .(one), Hom.reflexion => s
    | .(one), .(one), Hom.rightCompReflexion => g ≫ s
    | .(one), .(one), Hom.leftCompReflexion => f ≫ s) =
    (match one, zero, Hom.right with
      | x, .(x), Hom.id .(x) =>
        𝟙
          (match x with
          | zero => B
          | one => A)
      | .(one), .(zero), Hom.left => f
      | .(one), .(zero), Hom.right => g
      | .(zero), .(one), Hom.reflexion => s
      | .(one), .(one), Hom.rightCompReflexion => g ≫ s
      | .(one), .(one), Hom.leftCompReflexion => f ≫ s) ≫
      match zero, one, Hom.reflexion with
      | x, .(x), Hom.id .(x) =>
        𝟙
          (match x with
          | zero => B
          | one => A)
      | .(one), .(zero), Hom.left => f
      | .(one), .(zero), Hom.right => g
      | .(zero), .(one), Hom.reflexion => s
      | .(one), .(one), Hom.rightCompReflexion => g ≫ s
      | .(one), .(one), Hom.leftCompReflexion => f ≫ s

Tactic:
simp only [Category.id_comp, Category.comp_id, Category.assoc, sl, sr,
        reassoc_of% sl, reassoc_of% sr]

Goal state after:
case right.reflexion
C : Type u
inst✝ : Category.{v, u} C
A B : C
f g : A ⟶ B
s : B ⟶ A
sl : s ≫ f = 𝟙 B
sr : s ≫ g = 𝟙 B
⊢ (match one, one, Hom.right ≫ Hom.reflexion with
    | x, .(x), Hom.id .(x) =>
      𝟙
        (match x with
        | zero => B
        | one => A)
    | .(one), .(zero), Hom.left => f
    | .(one), .(zero), Hom.right => g
    | .(zero), .(one), Hom.reflexion => s
    | .(one), .(one), Hom.rightCompReflexion => g ≫ s
    | .(one), .(one), Hom.leftCompReflexion => f ≫ s) =
    g ≫ s