mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.Topology.Category.Profinite.Nobeling.Basic

Goal state before:
pp: case neg
I : Type u
C : Set (I → Bool)
J : I → Prop
inst✝ : (i : I) → Decidable (J i)
b : ↑(π C J)
i : I
hi : ¬J i
c : I → Bool
hc : c ∈ C
h : ↑((iso_map C J) ⟨Proj J c, ⋯⟩) = ↑((iso_map C J) b)
⊢ ↑⟨Proj J c, ⋯⟩ i = ↑b i

Tactic:
rcases b with ⟨_, d, hd, rfl⟩

Goal state after:
case neg
I : Type u
C : Set (I → Bool)
J : I → Prop
inst✝ : (i : I) → Decidable (J i)
i : I
hi : ¬J i
c : I → Bool
hc : c ∈ C
d : I → Bool
hd : d ∈ C
h : ↑((iso_map C J) ⟨Proj J c, ⋯⟩) = ↑((iso_map C J) ⟨Proj J d, ⋯⟩)
⊢ ↑⟨Proj J c, ⋯⟩ i = ↑⟨Proj J d, ⋯⟩ i
Module: Mathlib.Topology.Category.Profinite.Nobeling.Span

Goal state before:
pp: case neg.h₁
I : Type u
C : Set (I → Bool)
inst✝¹ : LinearOrder I
s : Finset I
inst✝ : WellFoundedLT I
x : ↑(π C fun x ↦ x ∈ s)
l : List I := s.sort fun x1 x2 ↦ x1 ≥ x2
a : I
as : List I
ha : List.IsChain (fun x1 x2 ↦ x1 > x2) (a :: as)
c : Products I →₀ ℤ
hc : ↑c.support ⊆ {m | ↑m ≤ as}
hmap :
  ∀ (g : Products I → ℤ → LocallyConstant ↑(π C fun x ↦ x ∈ s) ℤ),
    e (π C fun x ↦ x ∈ s) a * c.sum g = c.sum fun a_1 b ↦ e (π C fun x ↦ x ∈ s) a * g a_1 b
h✝ : ¬↑x a = true
m : Products I
⊢ c m ≠ 0 →
    c m • Products.eval (π C fun x ↦ x ∈ s) m ∈
      Submodule.span ℤ (Products.eval (π C fun x ↦ x ∈ s) '' {m | ↑m ≤ a :: as})

Tactic:
hm

Goal state after:
case neg.h₁
I : Type u
C : Set (I → Bool)
inst✝¹ : LinearOrder I
s : Finset I
inst✝ : WellFoundedLT I
x : ↑(π C fun x ↦ x ∈ s)
l : List I := s.sort fun x1 x2 ↦ x1 ≥ x2
a : I
as : List I
ha : List.IsChain (fun x1 x2 ↦ x1 > x2) (a :: as)
c : Products I →₀ ℤ
hc : ↑c.support ⊆ {m | ↑m ≤ as}
hmap :
  ∀ (g : Products I → ℤ → LocallyConstant ↑(π C fun x ↦ x ∈ s) ℤ),
    e (π C fun x ↦ x ∈ s) a * c.sum g = c.sum fun a_1 b ↦ e (π C fun x ↦ x ∈ s) a * g a_1 b
h✝ : ¬↑x a = true
m : Products I
hm : c m ≠ 0
⊢ c m • Products.eval (π C fun x ↦ x ∈ s) m ∈ Submodule.span ℤ (Products.eval (π C fun x ↦ x ∈ s) '' {m | ↑m ≤ a :: as})
Module: Mathlib.Topology.Category.Profinite.Nobeling.Basic

Goal state before:
pp: I : Type u
C : Set (I → Bool)
inst✝¹ : LinearOrder I
l : Products I
J : I → Prop
inst✝ : (j : I) → Decidable (J j)
h : isGood (π C J) l
i : I
hi : i ∈ ↑l
⊢ J i

Tactic:
by_contra h'

Goal state after:
I : Type u
C : Set (I → Bool)
inst✝¹ : LinearOrder I
l : Products I
J : I → Prop
inst✝ : (j : I) → Decidable (J j)
h : isGood (π C J) l
i : I
hi : i ∈ ↑l
h' : ¬J i
⊢ False
Module: Mathlib.Topology.Category.Profinite.Nobeling.Span

Goal state before:
pp: case neg
I : Type u
C : Set (I → Bool)
inst✝¹ : LinearOrder I
s : Finset I
inst✝ : WellFoundedLT I
x : ↑(π C fun x ↦ x ∈ s)
l : List I := s.sort fun x1 x2 ↦ x1 ≥ x2
a : I
as : List I
ha : List.IsChain (fun x1 x2 ↦ x1 > x2) (a :: as)
c : Products I →₀ ℤ
hc : ↑c.support ⊆ {m | ↑m ≤ as}
hmap :
  ∀ (g : Products I → ℤ → LocallyConstant ↑(π C fun x ↦ x ∈ s) ℤ),
    e (π C fun x ↦ x ∈ s) a * c.sum g = c.sum fun a_1 b ↦ e (π C fun x ↦ x ∈ s) a * g a_1 b
h✝ : ¬↑x a = true
⊢ ((1 - e (π C fun x ↦ x ∈ s) a) * c.sum fun i a ↦ a • Products.eval (π C fun x ↦ x ∈ s) i) ∈
    Submodule.span ℤ (Products.eval (π C fun x ↦ x ∈ s) '' {m | ↑m ≤ a :: as})

Tactic:
noncomm_ring
      -- we use `noncomm_ring` even though this is a commutative ring, because we want a weaker
      -- normalization which preserves multiplication order (i.e. doesn't use commutativity rules)
      rw [hmap]
      apply Submodule.add_mem
      · apply Submodule.finsuppSum_mem
        intro m hm
        apply Submodule.smul_mem
        apply Submodule.subset_span
        refine ⟨m, ⟨?_, rfl⟩⟩
        simp only [Set.mem_ofPred_eq]
        have hmas : m.val ≤ as :=
          hc (by simpa only [Finset.mem_coe, Finsupp.mem_support_iff] using hm)
        refine le_trans hmas ?_
        cases as with
        | nil => exact (List.nil_lt_cons a []).le
        | cons b bs =>
          apply le_of_lt
          rw [List.isChain_cons_cons] at ha
          exact (List.lt_iff_lex_lt _ _).mp (List.Lex.rel ha.1)
      · apply Submodule.smul_mem
        exact finsuppSum_mem_span_eval _ _ ha hc

Goal state after:
Module: Mathlib.Topology.Category.Profinite.Nobeling.ZeroLimit

Goal state before:
pp: I : Type u_1
inst✝ : LinearOrder I
f : LocallyConstant ↑{fun x ↦ false} ℤ
a✝ : f ∈ ⊤
⊢ ∃ a, a • eval {fun x ↦ false} nil = f

Tactic:
refine ⟨f default, ?_⟩

Goal state after:
I : Type u_1
inst✝ : LinearOrder I
f : LocallyConstant ↑{fun x ↦ false} ℤ
a✝ : f ∈ ⊤
⊢ f default • eval {fun x ↦ false} nil = f
Module: Mathlib.Topology.Category.Profinite.Nobeling.Basic

Goal state before:
pp: I : Type u
C : Set (I → Bool)
inst✝¹ : LinearOrder I
inst✝ : WellFoundedLT I
l : Products I
o : Ordinal.{u}
h : isGood C l
hsC : contained C o
i : I
hi : i ∈ ↑l
⊢ ord I i < o

Tactic:
by_contra h'

Goal state after:
I : Type u
C : Set (I → Bool)
inst✝¹ : LinearOrder I
inst✝ : WellFoundedLT I
l : Products I
o : Ordinal.{u}
h : isGood C l
hsC : contained C o
i : I
hi : i ∈ ↑l
h' : ¬ord I i < o
⊢ False
Module: Mathlib.Topology.CWComplex.Classical.Basic

Goal state before:
pp: case h.inr.inl
X : Type u_1
t : TopologicalSpace X
C D : Set X
inst✝ : RelCWComplex C D
n : ℕ
i : cell C (n + 1)
J : (m : ℕ) → Finset (cell C m)
p : (m : ℕ) → m ≤ n → cell C m → (m : ℕ) → Finset (cell C m)
hp :
  ∀ (m : ℕ) (a : m ≤ n) (i : cell C m), cellFrontier m i ⊆ D ∪ ⋃ m_1, ⋃ (_ : m_1 < m), ⋃ j ∈ p m a i m_1, openCell m_1 j
I : (m : ℕ) → Finset (cell C m) :=
  fun m ↦ J m ∪ (Finset.range n.succ).biUnion fun l ↦ (J l).biUnion fun y ↦ if h : l ≤ n then p l h y m else ∅
x : X
hx : x ∈ cellFrontier (n + 1) i
l : ℕ
hln : l < n.succ
j : cell C l
hj : j ∈ J l
hxj : x ∈ cellFrontier l j
⊢ x ∈ D ∨ ∃ i < n + 1, ∃ i_1 ∈ I i, x ∈ openCell i i_1

Tactic:
specialize hp l (Nat.le_of_lt_succ hln) j hxj

Goal state after:
case h.inr.inl
X : Type u_1
t : TopologicalSpace X
C D : Set X
inst✝ : RelCWComplex C D
n : ℕ
i : cell C (n + 1)
J : (m : ℕ) → Finset (cell C m)
p : (m : ℕ) → m ≤ n → cell C m → (m : ℕ) → Finset (cell C m)
I : (m : ℕ) → Finset (cell C m) :=
  fun m ↦ J m ∪ (Finset.range n.succ).biUnion fun l ↦ (J l).biUnion fun y ↦ if h : l ≤ n then p l h y m else ∅
x : X
hx : x ∈ cellFrontier (n + 1) i
l : ℕ
hln : l < n.succ
j : cell C l
hp : x ∈ D ∪ ⋃ m, ⋃ (_ : m < l), ⋃ j_1 ∈ p l ⋯ j m, openCell m j_1
hj : j ∈ J l
hxj : x ∈ cellFrontier l j
⊢ x ∈ D ∨ ∃ i < n + 1, ∃ i_1 ∈ I i, x ∈ openCell i i_1
Module: Mathlib.Topology.Category.Profinite.Nobeling.Successor

Goal state before:
pp: case refine_3
I : Type u
C : Set (I → Bool)
inst✝¹ : LinearOrder I
inst✝ : WellFoundedLT I
o : Ordinal.{u}
hC : IsClosed C
hsC : contained C (Order.succ o)
ho : o < Ordinal.type fun x1 x2 ↦ x1 < x2
f : LocallyConstant ↑C ℤ
hf :
  ⇑((LocallyConstant.comapₗ ℤ { toFun := CC'₁ C hsC ho, continuous_toFun := ⋯ }) f) =
    ⇑((LocallyConstant.comapₗ ℤ { toFun := CC'₀ C ho, continuous_toFun := ⋯ }) f)
C₀C : ↑(C0 C ho) → ↑C := fun x ↦ ⟨↑x, ⋯⟩
h₀ : Continuous C₀C
C₁C : ↑(π (C1 C ho) fun x ↦ ord I x < o) → ↑C := fun x ↦ ⟨SwapTrue o ↑x, ⋯⟩
h₁ : Continuous C₁C
x : I → Bool
hx : x ∈ C
⊢ ((πs C o)
        (LocallyConstant.piecewise' ⋯ ⋯ ⋯ (LocallyConstant.comap { toFun := C₀C, continuous_toFun := h₀ } f)
          (LocallyConstant.comap { toFun := C₁C, continuous_toFun := h₁ } f) ⋯))
      ⟨x, hx⟩ =
    f ⟨x, hx⟩

Tactic:
rw [← union_C0C1_eq C ho] at hx

Goal state after:
case refine_3
I : Type u
C : Set (I → Bool)
inst✝¹ : LinearOrder I
inst✝ : WellFoundedLT I
o : Ordinal.{u}
hC : IsClosed C
hsC : contained C (Order.succ o)
ho : o < Ordinal.type fun x1 x2 ↦ x1 < x2
f : LocallyConstant ↑C ℤ
hf :
  ⇑((LocallyConstant.comapₗ ℤ { toFun := CC'₁ C hsC ho, continuous_toFun := ⋯ }) f) =
    ⇑((LocallyConstant.comapₗ ℤ { toFun := CC'₀ C ho, continuous_toFun := ⋯ }) f)
C₀C : ↑(C0 C ho) → ↑C := fun x ↦ ⟨↑x, ⋯⟩
h₀ : Continuous C₀C
C₁C : ↑(π (C1 C ho) fun x ↦ ord I x < o) → ↑C := fun x ↦ ⟨SwapTrue o ↑x, ⋯⟩
h₁ : Continuous C₁C
x : I → Bool
hx✝ : x ∈ C
hx : x ∈ C0 C ho ∪ C1 C ho
⊢ ((πs C o)
        (LocallyConstant.piecewise' ⋯ ⋯ ⋯ (LocallyConstant.comap { toFun := C₀C, continuous_toFun := h₀ } f)
          (LocallyConstant.comap { toFun := C₁C, continuous_toFun := h₁ } f) ⋯))
      ⟨x, hx✝⟩ =
    f ⟨x, hx✝⟩
Module: Mathlib.Topology.CWComplex.Classical.Basic

Goal state before:
pp: X : Type u_1
t : TopologicalSpace X
C✝ D✝ : Set X
inst✝¹ : T2Space X
C D : Set X
inst✝ : RelCWComplex C D
n : ℕ∞
⊢ D ∪ ⋃ n_1, ⋃ j, openCell n_1 ↑j = D ∪ ⋃ m, ⋃ (_ : ↑m < n), ⋃ j, closedCell m j

Tactic:
rw [← RelCWComplex.iUnion_openCell_eq_iUnion_closedCell]
      congrm D ∪ ?_
      apply iUnion_congr fun m ↦ ?_
      rw [iUnion_subtype, iUnion_comm]
      rfl

Goal state after:
Module: Mathlib.Topology.Compactness.CompactSystem

Goal state before:
pp: case inr
α : Type u_1
S : Set (Set α)
h : IsCompactSystem S
h✝ : Nonempty α
⊢ IsCompactSystem (insert Set.univ S)

Tactic:
rw [IsCompactSystem.iff_nonempty_iInter] at h ⊢

Goal state after:
case inr
α : Type u_1
S : Set (Set α)
h : ∀ (C : ℕ → Set α), (∀ (i : ℕ), C i ∈ S) → (∀ (n : ℕ), (dissipate C n).Nonempty) → (⋂ i, C i).Nonempty
h✝ : Nonempty α
⊢ ∀ (C : ℕ → Set α), (∀ (i : ℕ), C i ∈ insert Set.univ S) → (∀ (n : ℕ), (dissipate C n).Nonempty) → (⋂ i, C i).Nonempty
Module: Mathlib.Topology.Compactification.OnePoint.Sphere

Goal state before:
pp: ι : Type u_1
V : Type u_2
inst✝⁷ : Fintype ι
inst✝⁶ : AddCommGroup V
inst✝⁵ : Module ℝ V
inst✝⁴ : FiniteDimensional ℝ V
inst✝³ : TopologicalSpace V
inst✝² : IsTopologicalAddGroup V
inst✝¹ : ContinuousSMul ℝ V
inst✝ : T2Space V
h : finrank ℝ V + 1 = Fintype.card ι
this✝ : Nonempty ι
v : EuclideanSpace ℝ ι := EuclideanSpace.single (Classical.arbitrary ι) 1
hv : ‖v‖ = 1
hv₀ : v ≠ 0
this : Fact (finrank ℝ (EuclideanSpace ℝ ι) = finrank ℝ V + 1)
hV : finrank ℝ V = finrank ℝ ↥(ℝ ∙ v)ᗮ
e : V ≃ₜ ↥(ℝ ∙ v)ᗮ := ↑⋯.some
⊢ OnePoint V ≃ₜ ↑(sphere 0 1)

Tactic:
exact e.onePointCongr.trans <| onePointHyperplaneHomeoUnitSphere hv

Goal state after:
Module: Mathlib.Topology.Category.Profinite.Nobeling.Successor

Goal state before:
pp: case neg
I : Type u
C : Set (I → Bool)
inst✝¹ : LinearOrder I
inst✝ : WellFoundedLT I
o : Ordinal.{u}
hsC : contained C (Order.succ o)
ho : o < Ordinal.type fun x1 x2 ↦ x1 < x2
q : ↑(GoodProducts (π C fun x ↦ ord I x < o))
l : ↑(MaxProducts C ho)
this : Inhabited I
h : ¬↑↑q = []
⊢ List.Lex (fun x1 x2 ↦ x1 < x2) ((↑↑q).head! :: (↑↑q).tail) (term I ho :: ↑(↑l).Tail)

Tactic:
apply List.Lex.rel

Goal state after:
case neg
I : Type u
C : Set (I → Bool)
inst✝¹ : LinearOrder I
inst✝ : WellFoundedLT I
o : Ordinal.{u}
hsC : contained C (Order.succ o)
ho : o < Ordinal.type fun x1 x2 ↦ x1 < x2
q : ↑(GoodProducts (π C fun x ↦ ord I x < o))
l : ↑(MaxProducts C ho)
this : Inhabited I
h : ¬↑↑q = []
⊢ (↑↑q).head! < term I ho
Module: Mathlib.Topology.Category.Profinite.Nobeling.Successor

Goal state before:
pp: case neg
I : Type u
C : Set (I → Bool)
inst✝¹ : LinearOrder I
inst✝ : WellFoundedLT I
o : Ordinal.{u}
hsC : contained C (Order.succ o)
ho : o < Ordinal.type fun x1 x2 ↦ x1 < x2
q : ↑(GoodProducts (π C fun x ↦ ord I x < o))
l : ↑(MaxProducts C ho)
this : Inhabited I
h : ¬↑↑q = []
⊢ (↑↑q).head! < term I ho

Tactic:
← Ordinal.typein_lt_typein (· < ·)

Goal state after:
case neg
I : Type u
C : Set (I → Bool)
inst✝¹ : LinearOrder I
inst✝ : WellFoundedLT I
o : Ordinal.{u}
hsC : contained C (Order.succ o)
ho : o < Ordinal.type fun x1 x2 ↦ x1 < x2
q : ↑(GoodProducts (π C fun x ↦ ord I x < o))
l : ↑(MaxProducts C ho)
this : Inhabited I
h : ¬↑↑q = []
⊢ (Ordinal.typein fun x1 x2 ↦ x1 < x2).toRelEmbedding (↑↑q).head! <
    (Ordinal.typein fun x1 x2 ↦ x1 < x2).toRelEmbedding (term I ho)
Module: Mathlib.Topology.Compactness.CountablyCompact

Goal state before:
pp: case neg
E : Type u_2
inst✝¹ : TopologicalSpace E
inst✝ : T1Space E
A : Set E
h : ∀ B ⊆ A, B.Infinite → ∃ a ∈ A, AccPt a (𝓟 B)
x : ℕ → E
hx : ∀ᶠ (n : ℕ) in cofinite, x n ∈ A
hfin : (range x).Infinite
⊢ ∃ a ∈ A, MapClusterPt a cofinite x

Tactic:
obtain ⟨a, haA, hacc⟩ := h (Set.range x ∩ A) inter_subset_right <| by
        rw [eventually_iff, mem_cofinite, compl_ofPred] at hx
        exact hfin.inter_of_finite_sdiff (hx.image x |>.subset (by grind))
      refine ⟨a, haA, ?_⟩
      simp_rw [mapClusterPt_iff_frequently, frequently_cofinite_iff_infinite]
      exact fun s hs ↦ Infinite.of_accPt (hacc.nhds_inter hs) |>.mono (by grind) |>.of_image x

Goal state after:
Module: Mathlib.Topology.Homotopy.LocallyContractible

Goal state before:
pp: case refine_2
X : Type u_1
Y : Type u_2
inst✝³ : TopologicalSpace X
inst✝² : TopologicalSpace Y
x y : X
ι : Type u_3
inst✝¹ : StronglyLocallyContractibleSpace X
inst✝ : StronglyLocallyContractibleSpace Y
⊢ ∀ (x : X × Y) (i : Set X × Set Y),
    (match x with
      | (x, y) =>
        match i with
        | (Ux, Uy) => (Ux ∈ 𝓝 x ∧ ContractibleSpace ↑Ux) ∧ Uy ∈ 𝓝 y ∧ ContractibleSpace ↑Uy) →
      ContractibleSpace
        ↑(match i with
          | (Ux, Uy) => Ux ×ˢ Uy)

Tactic:
intro (x, y) (Ux, Uy) ⟨hUx, hUy⟩
    have : ContractibleSpace Ux := hUx.2
    have : ContractibleSpace Uy := hUy.2
    exact (Homeomorph.Set.prod Ux Uy).contractibleSpace

Goal state after:
Module: Mathlib.Topology.Homotopy.HomotopyGroup

Goal state before:
pp: case mpr
N : Type u_1
M : Type u_3
y : M ⊕ N → ↑I
⊢ y ∘ Sum.inl ∈ Cube.boundary M ∨ y ∘ Sum.inr ∈ Cube.boundary N → y ∈ Cube.boundary (M ⊕ N)

Tactic:
rintro (⟨m, hm⟩ | ⟨n, hn⟩)

Goal state after:
case mpr.inl
N : Type u_1
M : Type u_3
y : M ⊕ N → ↑I
m : M
hm : (y ∘ Sum.inl) m = 0 ∨ (y ∘ Sum.inl) m = 1
⊢ y ∈ Cube.boundary (M ⊕ N)

case mpr.inr
N : Type u_1
M : Type u_3
y : M ⊕ N → ↑I
n : N
hn : (y ∘ Sum.inr) n = 0 ∨ (y ∘ Sum.inr) n = 1
⊢ y ∈ Cube.boundary (M ⊕ N)
Module: Mathlib.Topology.MetricSpace.HausdorffAlexandroff

Goal state before:
pp: X : Type u_1
inst✝² : Nonempty X
inst✝¹ : MetricSpace X
inst✝ : CompactSpace X
this : TopologicalSpace.SeparableSpace X := TopologicalSpace.SecondCountableTopology.to_separableSpace
emb : X → ℕ → ↑unitInterval
h_emb : Topology.IsEmbedding emb
KH : Set (ℕ → ↑unitInterval) := Set.range emb
g : X ≃ₜ ↑KH := h_emb.toHomeomorph
KC : Set (ℕ → Bool) := cantorToHilbert ⁻¹' KH
hKC_closed : IsClosed KC
f : (ℕ → Bool) → ℕ → Bool
hf_continuous : Continuous f
hf_surjective : Set.range f = KC
f' : (ℕ → Bool) → ↑KC := Subtype.coind f ⋯
⊢ Set.SurjOn f Set.univ KC

Tactic:
by grind [Set.SurjOn]

Goal state after:
Module: Mathlib.Topology.MetricSpace.HolderNorm

Goal state before:
pp: Y : Type u_2
inst✝¹ : PseudoEMetricSpace Y
r : ℝ≥0
X : Type u_3
inst✝ : PseudoMetricSpace X
f : X → Y
s : ℝ≥0
A : Set X
hf : ∃ C, HolderOnWith C r f A
hs : s ≤ r
hA : Bornology.IsBounded A
⊢ ∃ C, HolderOnWith C s f A

Tactic:
by
  simp_rw [← HolderWith.restrict_iff] at *
  have : BoundedSpace A := boundedSpace_val_set_iff.2 hA
  exact MemHolder.of_le hf hs

Goal state after:
Module: Mathlib.Topology.MetricSpace.Infsep

Goal state before:
pp: α : Type u_1
inst✝ : EDist α
s : Set α
hs : s.Finite
x✝ : ℝ≥0∞
⊢ x✝ ≤ s.einfsep ↔ x✝ ≤ ⋯.toFinset.inf (uncurry edist)

Tactic:
simp_rw [le_einfsep_iff, imp_forall_iff, Finset.le_inf_iff, Finite.mem_toFinset, mem_offDiag,
    Prod.forall, uncurry_apply_pair, and_imp]

Goal state after:
Module: Mathlib.Topology.MetricSpace.Infsep

Goal state before:
pp: α : Type u_1
inst✝ : PseudoMetricSpace α
x y z : α
hxy : x ≠ y
hyz : y ≠ z
hxz : x ≠ z
⊢ {x, y, z}.infsep = min (min (dist x y) (dist x z)) (dist y z)

Tactic:
simp only [infsep, einfsep_triple hxy hyz hxz, ENNReal.toReal_inf, edist_ne_top x y,
    edist_ne_top x z, edist_ne_top y z, dist_edist, Ne, inf_eq_top_iff, and_self_iff,
    not_false_iff]

Goal state after:
Module: Mathlib.Topology.MetricSpace.GromovHausdorff

Goal state before:

Tactic:
diam (range Φ ∪ range Ψ) ≤ diam (range Φ) + dist (Φ xX) (Ψ z) + diam (range Ψ) :=
          diam_union (mem_range_self _) (mem_range_self _)
        _ ≤
            diam (univ : Set X) + (diam (univ : Set X) + 1 + diam (univ : Set Y)) +
              diam (univ : Set Y) := by
          rw [DΦ, DΨ]
          gcongr
        _ = 2 * diam (univ : Set X) + 1 + 2 * diam (univ : Set Y) := by ring

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

Goal state before:
pp: case h.a
α : Type u_1
inst✝¹ : CompleteLinearOrder α
t : TopologicalSpace α
inst✝ : IsLower α
U : Set α
hU : ¬U = univ
hO : IsOpen[t] U
S : Set (Set α)
hS1 : S ⊆ insert univ {s | ∃ a, (Ici a)ᶜ = s}
hS2 : U = ⋃₀ S
hUS : univ ∉ S
⊢ Ici (sSup {a | (Ici a)ᶜ ∈ S}) ⊆ ⋂₀ (compl '' S)

Tactic:
intro b

Goal state after:
case h.a
α : Type u_1
inst✝¹ : CompleteLinearOrder α
t : TopologicalSpace α
inst✝ : IsLower α
U : Set α
hU : ¬U = univ
hO : IsOpen[t] U
S : Set (Set α)
hS1 : S ⊆ insert univ {s | ∃ a, (Ici a)ᶜ = s}
hS2 : U = ⋃₀ S
hUS : univ ∉ S
b : α
⊢ b ∈ Ici (sSup {a | (Ici a)ᶜ ∈ S}) → b ∈ ⋂₀ (compl '' S)
Module: Mathlib.Topology.Order.LowerUpperTopology

Goal state before:
pp: case a
α : Type u_1
inst✝¹ : CompleteLinearOrder α
t : TopologicalSpace α
inst✝ : IsLower α
U : Set α
hU : ¬U = univ
hO : IsOpen[t] U
S : Set (Set α)
hS1 : S ⊆ insert univ {s | ∃ a, (Ici a)ᶜ = s}
hS2 : U = ⋃₀ S
hUS : univ ∉ S
⊢ ⋂₀ (compl '' S) ⊆ Ici (sSup {a | (Ici a)ᶜ ∈ S})

Tactic:
intro b

Goal state after:
case a
α : Type u_1
inst✝¹ : CompleteLinearOrder α
t : TopologicalSpace α
inst✝ : IsLower α
U : Set α
hU : ¬U = univ
hO : IsOpen[t] U
S : Set (Set α)
hS1 : S ⊆ insert univ {s | ∃ a, (Ici a)ᶜ = s}
hS2 : U = ⋃₀ S
hUS : univ ∉ S
b : α
⊢ b ∈ ⋂₀ (compl '' S) → b ∈ Ici (sSup {a | (Ici a)ᶜ ∈ S})
Module: Mathlib.Topology.MetricSpace.GromovHausdorff

Goal state before:
pp: X : Type u
inst✝⁵ : MetricSpace X
inst✝⁴ : CompactSpace X
inst✝³ : Nonempty X
Y : Type v
inst✝² : MetricSpace Y
inst✝¹ : CompactSpace Y
inst✝ : Nonempty Y
s : Set X
Φ : ↑s → Y
ε₁ ε₂ ε₃ : ℝ
hs : ∀ (x : X), ∃ y ∈ s, dist x y ≤ ε₁
hs' : ∀ (x : Y), ∃ y, dist x (Φ y) ≤ ε₃
H : ∀ (x y : ↑s), |dist x y - dist (Φ x) (Φ y)| ≤ ε₂
⊢ ghDist X Y ≤ ε₁ + ε₂ / 2 + ε₃

Tactic:
refine le_of_forall_pos_le_add fun δ δ0 => ?_

Goal state after:
X : Type u
inst✝⁵ : MetricSpace X
inst✝⁴ : CompactSpace X
inst✝³ : Nonempty X
Y : Type v
inst✝² : MetricSpace Y
inst✝¹ : CompactSpace Y
inst✝ : Nonempty Y
s : Set X
Φ : ↑s → Y
ε₁ ε₂ ε₃ : ℝ
hs : ∀ (x : X), ∃ y ∈ s, dist x y ≤ ε₁
hs' : ∀ (x : Y), ∃ y, dist x (Φ y) ≤ ε₃
H : ∀ (x y : ↑s), |dist x y - dist (Φ x) (Φ y)| ≤ ε₂
δ : ℝ
δ0 : 0 < δ
⊢ ghDist X Y ≤ ε₁ + ε₂ / 2 + ε₃ + δ
Module: Mathlib.Topology.MetricSpace.GromovHausdorff

Goal state before:
pp: δ : ℝ
δpos : δ > 0
ε : ℝ := 2 / 5 * δ
εpos : 0 < ε
s : (p : GHSpace) → Set p.Rep
hs : ∀ (p : GHSpace), (s p).Finite ∧ univ ⊆ ⋃ x ∈ s p, ball x ε
⊢ ∃ β x F, ∀ (x y : GHSpace), F x = F y → dist x y ≤ δ

Tactic:
let N := fun p : GHSpace => Nat.card (s p)

Goal state after:
δ : ℝ
δpos : δ > 0
ε : ℝ := 2 / 5 * δ
εpos : 0 < ε
s : (p : GHSpace) → Set p.Rep
hs : ∀ (p : GHSpace), (s p).Finite ∧ univ ⊆ ⋃ x ∈ s p, ball x ε
N : GHSpace → ℕ := fun p ↦ Nat.card ↑(s p)
⊢ ∃ β x F, ∀ (x y : GHSpace), F x = F y → dist x y ≤ δ
Module: Mathlib.Topology.MetricSpace.GromovHausdorff

Goal state before:
pp: δ : ℝ
δpos : δ > 0
ε : ℝ := 2 / 5 * δ
εpos : 0 < ε
s : (p : GHSpace) → Set p.Rep
hs : ∀ (p : GHSpace), (s p).Finite ∧ univ ⊆ ⋃ x ∈ s p, ball x ε
N : GHSpace → ℕ := fun p ↦ Nat.card ↑(s p)
E : (p : GHSpace) → ↑(s p) ≃ Fin (Nat.card ↑(s p)) := fun p ↦ Finite.equivFin ↑(s p)
F : GHSpace → (n : ℕ) × (Fin n → Fin n → ℤ) := fun p ↦ ⟨N p, fun a b ↦ ⌊ε⁻¹ * dist ((E p).symm a) ((E p).symm b)⌋⟩
p q : GHSpace
hpq : F p = F q
Npq : N p = N q
Ψ : ↑(s p) → ↑(s q) := fun x ↦ (E q).symm (Fin.cast Npq ((E p) x))
Φ : ↑(s p) → q.Rep := fun x ↦ ↑(Ψ x)
x : q.Rep
this : x ∈ ⋃ y ∈ s q, ball y ε
y : q.Rep
ys : y ∈ s q
hy : x ∈ ball y ε
i : ℕ := ↑((E q) ⟨y, ys⟩)
hi : ↑((E q) ⟨y, ys⟩) < Nat.card ↑(s q) := Fin.is_lt ((E q) ⟨y, ys⟩)
ihi_eq : ⟨i, hi⟩ = (E q) ⟨y, ys⟩
hiq : i < N q
hip : i < N p
z : ↑(s p) := (E p).symm ⟨i, hip⟩
C1 : (E p) z = ⟨i, hip⟩
C2 : Fin.cast Npq ⟨i, hip⟩ = ⟨i, hi⟩
⊢ (E q).symm ⟨i, hi⟩ = ⟨y, ys⟩

Tactic:
rw [ihi_eq]

Goal state after:
δ : ℝ
δpos : δ > 0
ε : ℝ := 2 / 5 * δ
εpos : 0 < ε
s : (p : GHSpace) → Set p.Rep
hs : ∀ (p : GHSpace), (s p).Finite ∧ univ ⊆ ⋃ x ∈ s p, ball x ε
N : GHSpace → ℕ := fun p ↦ Nat.card ↑(s p)
E : (p : GHSpace) → ↑(s p) ≃ Fin (Nat.card ↑(s p)) := fun p ↦ Finite.equivFin ↑(s p)
F : GHSpace → (n : ℕ) × (Fin n → Fin n → ℤ) := fun p ↦ ⟨N p, fun a b ↦ ⌊ε⁻¹ * dist ((E p).symm a) ((E p).symm b)⌋⟩
p q : GHSpace
hpq : F p = F q
Npq : N p = N q
Ψ : ↑(s p) → ↑(s q) := fun x ↦ (E q).symm (Fin.cast Npq ((E p) x))
Φ : ↑(s p) → q.Rep := fun x ↦ ↑(Ψ x)
x : q.Rep
this : x ∈ ⋃ y ∈ s q, ball y ε
y : q.Rep
ys : y ∈ s q
hy : x ∈ ball y ε
i : ℕ := ↑((E q) ⟨y, ys⟩)
hi : ↑((E q) ⟨y, ys⟩) < Nat.card ↑(s q) := Fin.is_lt ((E q) ⟨y, ys⟩)
ihi_eq : ⟨i, hi⟩ = (E q) ⟨y, ys⟩
hiq : i < N q
hip : i < N p
z : ↑(s p) := (E p).symm ⟨i, hip⟩
C1 : (E p) z = ⟨i, hip⟩
C2 : Fin.cast Npq ⟨i, hip⟩ = ⟨i, hi⟩
⊢ (E q).symm ((E q) ⟨y, ys⟩) = ⟨y, ys⟩
Module: Mathlib.Topology.Sheaves.Skyscraper

Goal state before:
pp: X : TopCat
p₀ : ↑X
inst✝³ : (U : Opens ↑X) → Decidable (p₀ ∈ U)
C : Type v
inst✝² : Category.{u, v} C
A : C
inst✝¹ : HasTerminal C
inst✝ : HasColimits C
𝓕 : Presheaf C X
c : C
f : 𝓕 ⟶ skyscraperPresheaf p₀ c
U V : (OpenNhds p₀)ᵒᵖ
inc : U ⟶ V
⊢ (𝓕.map ((OpenNhds.inclusion p₀).op.map inc) ≫ f.app (op ((OpenNhds.inclusion p₀).obj (unop V)))) ≫ eqToHom ⋯ =
    f.app (op ((OpenNhds.inclusion p₀).obj (unop U))) ≫ eqToHom ⋯

Tactic:
comp_eqToHom_iff,

Goal state after:
X : TopCat
p₀ : ↑X
inst✝³ : (U : Opens ↑X) → Decidable (p₀ ∈ U)
C : Type v
inst✝² : Category.{u, v} C
A : C
inst✝¹ : HasTerminal C
inst✝ : HasColimits C
𝓕 : Presheaf C X
c : C
f : 𝓕 ⟶ skyscraperPresheaf p₀ c
U V : (OpenNhds p₀)ᵒᵖ
inc : U ⟶ V
⊢ 𝓕.map ((OpenNhds.inclusion p₀).op.map inc) ≫ f.app (op ((OpenNhds.inclusion p₀).obj (unop V))) =
    (f.app (op ((OpenNhds.inclusion p₀).obj (unop U))) ≫ eqToHom ⋯) ≫ eqToHom ⋯
Module: Mathlib.Topology.Sheaves.Alexandrov

Goal state before:
pp: X✝ : Type v
inst✝⁶ : TopologicalSpace X✝
inst✝⁵ : Preorder X✝
inst✝⁴ : Topology.IsUpperSet X✝
C : Type u
inst✝³ : Category.{v, u} C
inst✝² : HasLimits C
F✝ : X✝ ⥤ C
X : TopCat
inst✝¹ : Preorder ↑X
inst✝ : Topology.IsUpperSet ↑X
F : ↑X ⥤ C
α : Type v
Us : α → Opens ↑X
S : Cone ((ObjectProperty.ι fun V ↦ ∃ i, V ≤ Us i).op ⋙ principalsKanExtension F)
m : S.pt ⟶ ((principalsKanExtension F).mapCone (opensLeCoverCocone Us).op).pt
⊢ (∀ (j : (ObjectProperty.FullSubcategory fun V ↦ ∃ i, V ≤ Us i)ᵒᵖ),
      m ≫ ((principalsKanExtension F).mapCone (opensLeCoverCocone Us).op).π.app j = S.π.app j) →
    m = limit.lift (generator (iSup Us) ⋙ F) (lowerCone Us S)

Tactic:
hm

Goal state after:
X✝ : Type v
inst✝⁶ : TopologicalSpace X✝
inst✝⁵ : Preorder X✝
inst✝⁴ : Topology.IsUpperSet X✝
C : Type u
inst✝³ : Category.{v, u} C
inst✝² : HasLimits C
F✝ : X✝ ⥤ C
X : TopCat
inst✝¹ : Preorder ↑X
inst✝ : Topology.IsUpperSet ↑X
F : ↑X ⥤ C
α : Type v
Us : α → Opens ↑X
S : Cone ((ObjectProperty.ι fun V ↦ ∃ i, V ≤ Us i).op ⋙ principalsKanExtension F)
m : S.pt ⟶ ((principalsKanExtension F).mapCone (opensLeCoverCocone Us).op).pt
hm :
  ∀ (j : (ObjectProperty.FullSubcategory fun V ↦ ∃ i, V ≤ Us i)ᵒᵖ),
    m ≫ ((principalsKanExtension F).mapCone (opensLeCoverCocone Us).op).π.app j = S.π.app j
⊢ m = limit.lift (generator (iSup Us) ⋙ F) (lowerCone Us S)