mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.Topology.Compactness.CountablyCompact

Goal state before:
pp: ι : Type u_1
E : Type u_2
F : Type u_3
inst✝³ : TopologicalSpace E
inst✝² : TopologicalSpace F
A✝ B : Set E
inst✝¹ : SequentialSpace E
inst✝ : CountablyCompactSpace E
x : ℕ → E
hx : ∀ (x_1 : E) (x_2 : ℕ → ℕ), StrictMono x_2 → ¬Tendsto (x ∘ x_2) atTop (𝓝 x_1)
A : Set E := ⋃ i, closure[inst✝³] {x i}
this : IsCountablyCompact A
a : E
ha : a ∈ A ∧ MapClusterPt a atTop x
⊢ ∃ k, ∀ n > k, a ∉ closure[inst✝³] {x n}

Tactic:
by
    by_contra!
    obtain ⟨φ, hφ1, hφ2⟩ := Nat.exists_strictMono_subsequence this
    refine hx a φ hφ1 (tendsto_atTop_nhds.2 fun U ha hUo => ⟨0, fun n _ => ?_⟩)
    simpa using mem_closure_iff.1 (hφ2 n) U hUo ha

Goal state after:
Module: Mathlib.Topology.Filter

Goal state before:
pp: ι : Sort u_1
α : Type u_2
l : Filter α
p : ι → Prop
s : ι → Set α
h : l.HasBasis p s
⊢ (𝓝 l).HasBasis p fun i ↦ Iic (𝓟 (s i))

Tactic:
rw [nhds_eq]

Goal state after:
ι : Sort u_1
α : Type u_2
l : Filter α
p : ι → Prop
s : ι → Set α
h : l.HasBasis p s
⊢ (l.lift' (Iic ∘ 𝓟)).HasBasis p fun i ↦ Iic (𝓟 (s i))
Module: Mathlib.Topology.Filter

Goal state before:
pp: X : Type u_4
l : Filter X
⊢ ∀ s ∈ l, ∀ᶠ (a : X) in l, s ∈ pure a

Tactic:
exact fun s hs ↦ Eventually.mono hs fun x ↦ id

Goal state after:
Module: Mathlib.Topology.Filter

Goal state before:
pp: X : Type u_4
inst✝ : TopologicalSpace X
x : X
⊢ ⨅ s, ⨅ (_ : IsOpen[inst✝] s), ⨅ (_ : x ∈ s), 𝓟 s = comap 𝓝 (𝓝 (𝓝 x))

Tactic:
by
      simp +contextual only [nhds_nhds, comap_iInf, comap_principal,
        Iic_principal, preimage_ofPred_eq, ← mem_interior_iff_mem_nhds, ofPred_mem_eq,
        IsOpen.interior_eq]

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

Goal state before:
pp: t : ↑I
⊢ ↑(qRight (t, 0)) = if ↑t ≤ 1 / 2 then 2 * ↑t else 1

Tactic:
simp only [qRight, coe_zero, add_zero, div_one]

Goal state after:
t : ↑I
⊢ ↑(Set.projIcc 0 1 qRight._proof_1 (2 * ↑t)) = if ↑t ≤ 1 / 2 then 2 * ↑t else 1
Module: Mathlib.Topology.Instances.RatLemmas

Goal state before:
pp: H : (cocompact ℚ).IsCountablyGenerated
x : ℕ → ℚ
hxc : Tendsto x atTop (cocompact ℚ)
hx0 : Tendsto x atTop (𝓝 0)
n : ℕ
hn : x n ∉ insert 0 (range x)
⊢ False

Tactic:
exact hn (Or.inr ⟨n, rfl⟩)

Goal state after:
Module: Mathlib.Topology.Maps.Proper.UniversallyClosed

Goal state before:
pp: case mpr
X : Type u
Y : Type v
inst✝¹ : TopologicalSpace X
inst✝ : TopologicalSpace Y
f : X → Y
H : Continuous f ∧ ∀ (Z : Type u) [inst : TopologicalSpace Z], IsClosedMap (Prod.map f id)
⊢ IsProperMap f

Tactic:
rw [isProperMap_iff_isClosedMap_ultrafilter]

Goal state after:
case mpr
X : Type u
Y : Type v
inst✝¹ : TopologicalSpace X
inst✝ : TopologicalSpace Y
f : X → Y
H : Continuous f ∧ ∀ (Z : Type u) [inst : TopologicalSpace Z], IsClosedMap (Prod.map f id)
⊢ Continuous f ∧ IsClosedMap (Prod.map f id)
Module: Mathlib.Topology.EMetricSpace.PairReduction

Goal state before:
pp: T : Type u_1
inst✝² : PseudoEMetricSpace T
a c : ℝ≥0∞
J : Finset T
inst✝¹ : DecidableEq T
E : Type u_2
inst✝ : PseudoEMetricSpace E
ha : 1 < a
f : T → E
hJ : J.Nonempty
s : T
hs : s ∈ J
t : T
ht : t ∈ J
hst : edist ⟨s, hs⟩ ⟨t, ht⟩ ≤ c
P : ℕ → Prop := ⋯
l : ℕ := ⋯
hsV : s ∈ (logSizeBallSeq J hJ a c l).finset
htV : t ∈ (logSizeBallSeq J hJ a c l).finset
h : edist (logSizeBallSeq J hJ a c l).point s ≤ (↑(logSizeBallSeq J hJ a c l).radius - 1) * c
hsB : s ∈ (logSizeBallSeq J hJ a c l).ball c
⊢ (↑(logSizeBallSeq J hJ a c l).radius - 1) * c + c = ↑(logSizeBallSeq J hJ a c l).radius * c

Tactic:
← one_mul c

Goal state after:
T : Type u_1
inst✝² : PseudoEMetricSpace T
a c : ℝ≥0∞
J : Finset T
inst✝¹ : DecidableEq T
E : Type u_2
inst✝ : PseudoEMetricSpace E
ha : 1 < a
f : T → E
hJ : J.Nonempty
s : T
hs : s ∈ J
t : T
ht : t ∈ J
hst : edist ⟨s, hs⟩ ⟨t, ht⟩ ≤ c
P : ℕ → Prop := fun l ↦ s ∈ (logSizeBallSeq J hJ a c l).finset ∧ t ∈ (logSizeBallSeq J hJ a c l).finset
l : ℕ := Nat.findGreatest P (#J - 1)
hsV : s ∈ (logSizeBallSeq J hJ a c l).finset
htV : t ∈ (logSizeBallSeq J hJ a c l).finset
h : edist (logSizeBallSeq J hJ a c l).point s ≤ (↑(logSizeBallSeq J hJ a c l).radius - 1) * c
hsB : s ∈ (logSizeBallSeq J hJ a c l).ball c
⊢ (↑(logSizeBallSeq J hJ a c l).radius - 1) * c + 1 * c = ↑(logSizeBallSeq J hJ a c l).radius * c
Module: Mathlib.Topology.MetricSpace.HolderNorm

Goal state before:
pp: X : Type u_1
Y : Type u_2
inst✝¹ : MetricSpace X
inst✝ : EMetricSpace Y
C r : ℝ≥0
f : X → Y
hf : HolderWith C r f
⊢ eHolderNorm r f ≤ ↑C

Tactic:
exact hf.eHolderNorm_le

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

Goal state before:
pp: X : Type u
inst✝² : MetricSpace X
inst✝¹ : CompactSpace X
inst✝ : Nonempty X
p : NonemptyCompacts ↥(lp (fun n ↦ ℝ) ∞)
Ψ : X → ↥(lp (fun n ↦ ℝ) ∞)
isomΨ : Isometry Ψ
rangeΨ : range Ψ = ↑p
f : ↑(range Ψ) ≃ᵢ ↑(range (kuratowskiEmbedding X))
⊢ (↑(range Ψ) ≃ᵢ ↥{ carrier := range (kuratowskiEmbedding X), isCompact' := ⋯, nonempty' := ⋯ }) =
    (↥p ≃ᵢ ↑(range (kuratowskiEmbedding X)))

Tactic:
rangeΨ

Goal state after:
X : Type u
inst✝² : MetricSpace X
inst✝¹ : CompactSpace X
inst✝ : Nonempty X
p : NonemptyCompacts ↥(lp (fun n ↦ ℝ) ∞)
Ψ : X → ↥(lp (fun n ↦ ℝ) ∞)
isomΨ : Isometry Ψ
rangeΨ : range Ψ = ↑p
f : ↑(range Ψ) ≃ᵢ ↑(range (kuratowskiEmbedding X))
⊢ (↑↑p ≃ᵢ ↥{ carrier := range (kuratowskiEmbedding X), isCompact' := ⋯, nonempty' := ⋯ }) =
    (↥p ≃ᵢ ↑(range (kuratowskiEmbedding X)))
Module: Mathlib.Topology.MetricSpace.Infsep

Goal state before:
pp: α : Type u_1
inst✝ : PseudoMetricSpace α
s : Finset α
⊢ (↑s).infsep = if hs : s.offDiag.Nonempty then s.offDiag.inf' hs (uncurry dist) else 0

Tactic:
have H : (s : Set α).Nontrivial ↔ s.offDiag.Nonempty := by
    rw [← Set.offDiag_nonempty, ← Finset.coe_offDiag, Finset.coe_nonempty]
  split_ifs with hs
  · classical simp_rw [(H.mpr hs).infsep_of_fintype, ← Finset.coe_offDiag, Finset.toFinset_coe]
  · exact (not_nontrivial_iff.mp (H.mp.mt hs)).infsep_zero

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

Goal state before:
pp: α : Type u_1
inst✝¹ : MetricSpace α
s : Set α
inst✝ : Finite ↑s
⊢ 0 < s.infsep ↔ s.Nontrivial

Tactic:
rw [infsep_pos, einfsep_lt_top_iff, and_iff_right_iff_imp]
  exact fun _ => einfsep_pos_of_finite

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

Goal state before:
pp: case inl
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
inhabited_h✝ : Inhabited X
inhabited_h : Inhabited Y
p q : NonemptyCompacts ↥(lp (fun n ↦ ℝ) ∞)
hp : ⟦p⟧ = toGHSpace X
hq : ⟦q⟧ = toGHSpace Y
bound : hausdorffDist ↑p ↑q < diam univ + 1 + diam univ
Φ : X → ↥(lp (fun n ↦ ℝ) ∞)
Φisom : Isometry Φ
Φrange : range Φ = ↑p
Ψ : Y → ↥(lp (fun n ↦ ℝ) ∞)
Ψisom : Isometry Ψ
Ψrange : range Ψ = ↑q
I : diam (range Φ ∪ range Ψ) ≤ 2 * diam univ + 1 + 2 * diam univ
f : X ⊕ Y → ↥(lp (fun n ↦ ℝ) ∞) := ⋯
F : (X ⊕ Y) × (X ⊕ Y) → ℝ := ⋯
x y : X ⊕ Y
val✝ : X
⊢ f (inl val✝) ∈ range Φ

Tactic:
apply mem_range_self

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

Goal state before:
pp: case inr
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
inhabited_h✝ : Inhabited X
inhabited_h : Inhabited Y
p q : NonemptyCompacts ↥(lp (fun n ↦ ℝ) ∞)
hp : ⟦p⟧ = toGHSpace X
hq : ⟦q⟧ = toGHSpace Y
bound : hausdorffDist ↑p ↑q < diam univ + 1 + diam univ
Φ : X → ↥(lp (fun n ↦ ℝ) ∞)
Φisom : Isometry Φ
Φrange : range Φ = ↑p
Ψ : Y → ↥(lp (fun n ↦ ℝ) ∞)
Ψisom : Isometry Ψ
Ψrange : range Ψ = ↑q
I : diam (range Φ ∪ range Ψ) ≤ 2 * diam univ + 1 + 2 * diam univ
f : X ⊕ Y → ↥(lp (fun n ↦ ℝ) ∞) := ⋯
F : (X ⊕ Y) × (X ⊕ Y) → ℝ := ⋯
x y : X ⊕ Y
val✝ : Y
⊢ f (inr val✝) ∈ range Ψ

Tactic:
apply mem_range_self

Goal state after:
Module: Mathlib.Topology.Partial

Goal state before:
pp: case mpr
X : Type u_1
Y : Type u_2
inst✝¹ : TopologicalSpace X
inst✝ : TopologicalSpace Y
f : X →. Y
hf : ∀ {x : X} {y : Y}, y ∈ f x → PTendsto' f (𝓝 x) (𝓝 y)
s : Set Y
os : IsOpen[inst✝] s
⊢ IsOpen[inst✝¹] (f.preimage s)

Tactic:
rw [isOpen_iff_nhds]

Goal state after:
case mpr
X : Type u_1
Y : Type u_2
inst✝¹ : TopologicalSpace X
inst✝ : TopologicalSpace Y
f : X →. Y
hf : ∀ {x : X} {y : Y}, y ∈ f x → PTendsto' f (𝓝 x) (𝓝 y)
s : Set Y
os : IsOpen[inst✝] s
⊢ ∀ x ∈ f.preimage s, 𝓝 x ≤ 𝓟 (f.preimage s)
Module: Mathlib.Topology.Order.LawsonTopology

Goal state before:
pp: α : Type u_1
inst✝² : Preorder α
L S : TopologicalSpace α
inst✝¹ : IsLawson α
inst✝ : IsScott α univ
s : Set α
h : IsUpperSet s
⊢ IsOpen[lawson α] s ↔ IsOpen[S] s

Tactic:
@IsScott.topology_eq α univ _ S _

Goal state after:
α : Type u_1
inst✝² : Preorder α
L S : TopologicalSpace α
inst✝¹ : IsLawson α
inst✝ : IsScott α univ
s : Set α
h : IsUpperSet s
⊢ IsOpen[lawson α] s ↔ IsOpen[scott α univ] s
Module: Mathlib.Topology.Sheaves.Skyscraper

Goal state before:
pp: X : TopCat
p₀ : ↑X
inst✝² : (U : Opens ↑X) → Decidable (p₀ ∈ U)
C : Type v
inst✝¹ : Category.{u, v} C
A : C
inst✝ : HasTerminal C
y : ↑X
h✝ : p₀ ⤳ y
c : Cocone ((OpenNhds.inclusion y).op ⋙ skyscraperPresheaf p₀ A)
f : (skyscraperPresheafCoconeOfSpecializes p₀ A h✝).pt ⟶ c.pt
h : ∀ (j : (OpenNhds y)ᵒᵖ), (skyscraperPresheafCoconeOfSpecializes p₀ A h✝).ι.app j ≫ f = c.ι.app j
⊢ f = eqToHom ⋯ ≫ c.ι.app (op ⊤)

Tactic:
by
    dsimp
    rw [← h, skyscraperPresheafCoconeOfSpecializes_ι_app, eqToHom_trans_assoc, eqToHom_refl,
      Category.id_comp]

Goal state after:
Module: Mathlib.Topology.Sheaves.EtaleSpace

Goal state before:
pp: X : TopCat
C : Type u
inst✝⁴ : Category.{v, u} C
CC : C → Type v
FC : C → C → Type w
inst✝³ : (X Y : C) → FunLike (FC X Y) (CC X) (CC Y)
inst✝² : ConcreteCategory C FC
inst✝¹ : Limits.HasColimits C
F : Presheaf C X
inst✝ : Limits.PreservesFilteredColimits (forget C)
U : Opens ↑X
hF_bij : ∀ (x : ↑X) (hx : x ∈ U), Bijective ⇑(ConcreteCategory.hom (F.germ U x hx))
x : ↑X
hx : x ∈ U
⊢ Continuous fun s ↦
    (⟨(↑s).base, ⋯⟩, WithTopology.toTopology ⊥ ((ConcreteCategory.hom (F.germ U x hx)) (surjInv ⋯ (↑s).germ)))

Tactic:
by
    refine .prodMk (by fun_prop) ?_
    simp_rw [continuous_iff_continuousAt, ContinuousAt, nhds_discrete, tendsto_pure, nhds_subtype,
      eventually_comap]
    rintro ⟨g, hg⟩
    rcases hF_bij _ hg |>.surjective g.germ with ⟨f, hf⟩
    filter_upwards [g.eventually_nhds hg f hf]
    rintro _ ⟨hgU, hgf⟩ g' rfl
    congr 1
    rw [hgf, ← hf, leftInverse_surjInv (hF_bij _ _), leftInverse_surjInv (hF_bij _ _)]

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

Goal state before:
pp: case neg
t : Set GHSpace
C : ℝ
u : ℕ → ℝ
K : ℕ → ℕ
ulim : Tendsto u atTop (𝓝 0)
hdiam : ∀ p ∈ t, diam univ ≤ C
hcov : ∀ p ∈ t, ∀ (n : ℕ), ∃ s, #↑s ≤ ↑(K n) ∧ univ ⊆ ⋃ x ∈ s, ball x (u n)
δ : ℝ
δpos : δ > 0
ε : ℝ := 1 / 5 * δ
εpos : 0 < ε
n : ℕ
hn : ∀ n_1 ≥ n, dist (u n_1) 0 < ε
u_le_ε : u n ≤ ε
p : GHSpace
hp : ¬p ∉ t
s : Set p.Rep
scard : #↑s ≤ ↑(K n)
scover : univ ⊆ ⋃ x ∈ s, ball x (u n)
N : ℕ
hN : #↑s = ↑N
⊢ ∃ s, ∃ N ≤ K n, ∃ x, p ∈ t → univ ⊆ ⋃ x ∈ s, ball x (u n)

Tactic:
rw [hN, Nat.cast_le] at scard

Goal state after:
case neg
t : Set GHSpace
C : ℝ
u : ℕ → ℝ
K : ℕ → ℕ
ulim : Tendsto u atTop (𝓝 0)
hdiam : ∀ p ∈ t, diam univ ≤ C
hcov : ∀ p ∈ t, ∀ (n : ℕ), ∃ s, #↑s ≤ ↑(K n) ∧ univ ⊆ ⋃ x ∈ s, ball x (u n)
δ : ℝ
δpos : δ > 0
ε : ℝ := 1 / 5 * δ
εpos : 0 < ε
n : ℕ
hn : ∀ n_1 ≥ n, dist (u n_1) 0 < ε
u_le_ε : u n ≤ ε
p : GHSpace
hp : ¬p ∉ t
s : Set p.Rep
scover : univ ⊆ ⋃ x ∈ s, ball x (u n)
N : ℕ
scard : N ≤ K n
hN : #↑s = ↑N
⊢ ∃ s, ∃ N ≤ K n, ∃ x, p ∈ t → univ ⊆ ⋃ x ∈ s, ball x (u n)
Module: Mathlib.Topology.MetricSpace.GromovHausdorff

Goal state before:
pp: case neg
t : Set GHSpace
C : ℝ
u : ℕ → ℝ
K : ℕ → ℕ
ulim : Tendsto u atTop (𝓝 0)
hdiam : ∀ p ∈ t, diam univ ≤ C
hcov : ∀ p ∈ t, ∀ (n : ℕ), ∃ s, #↑s ≤ ↑(K n) ∧ univ ⊆ ⋃ x ∈ s, ball x (u n)
δ : ℝ
δpos : δ > 0
ε : ℝ := 1 / 5 * δ
εpos : 0 < ε
n : ℕ
hn : ∀ n_1 ≥ n, dist (u n_1) 0 < ε
u_le_ε : u n ≤ ε
p : GHSpace
hp : ¬p ∉ t
⊢ ∃ s, ∃ N ≤ K n, ∃ x, p ∈ t → univ ⊆ ⋃ x ∈ s, ball x (u n)

Tactic:
· rcases hcov _ (Set.not_notMem.1 hp) n with ⟨s, ⟨scard, scover⟩⟩
      rcases Cardinal.lt_aleph0.1 (scard.trans_lt Cardinal.natCast_lt_aleph0) with ⟨N, hN⟩
      rw [hN, Nat.cast_le] at scard
      have : #s = #(Fin N) := by rw [hN, Cardinal.mk_fin]
      obtain ⟨E⟩ := Quotient.exact this
      use s, N, scard, E
      simp only [scover, imp_true_iff]

Goal state after:
Module: Mathlib.Topology.Sion

Goal state before:
pp: E : Type u_1
F : Type u_2
β : Type u_3
inst✝¹¹ : LinearOrder β
X : Set E
Y : Set F
f : E → F → β
inst✝¹⁰ : TopologicalSpace E
inst✝⁹ : AddCommGroup E
inst✝⁸ : Module ℝ E
inst✝⁷ : IsTopologicalAddGroup E
inst✝⁶ : ContinuousSMul ℝ E
ne_X : X.Nonempty
kX : IsCompact X
hfy : ∀ y ∈ Y, LowerSemicontinuousOn (fun x ↦ f x y) X
hfy' : ∀ y ∈ Y, QuasiconvexOn ℝ X fun x ↦ f x y
inst✝⁵ : TopologicalSpace F
inst✝⁴ : AddCommGroup F
inst✝³ : Module ℝ F
cY : Convex ℝ Y
hfx : ∀ x ∈ X, UpperSemicontinuousOn (fun y ↦ f x y) Y
hfx' : ∀ x ∈ X, QuasiconcaveOn ℝ Y fun y ↦ f x y
inst✝² : DenselyOrdered β
inst✝¹ : IsTopologicalAddGroup F
inst✝ : ContinuousSMul ℝ F
t : β
hinfi_le : ∀ y0 ∈ Y, ∃ x ∈ X, f x y0 ≤ t
a : E
ha : a ∈ X
t' : β
htt' : t < t'
y1 y2 : { x // x ∈ Y }
ht : ∀ x ∈ X, t < max (f x ↑y1) (f x ↑y2)
ha' : IsMinOn (fun x ↦ max (f x ↑y1) (f x ↑y2)) X a
ht' : t' < max (f a ↑y1) (f a ↑y2)
J1 : Set ↑(segment ℝ ↑y1 ↑y2) := setOfPred_sublevelLeft_subset X Y f t t' y1 y2
mem_J1_iff : ∀ (z : ↑(segment ℝ ↑y1 ↑y2)), z ∈ J1 ↔ sublevelLeft X f t ↑z ⊆ sublevelLeft X f t' ↑y1
φ : ↑(segment ℝ ↑y1 ↑y2) ≃ₜ ↑(segment ℝ ↑y2 ↑y1) := Homeomorph.setCongr ⋯
J2 : Set ↑(segment ℝ ↑y1 ↑y2) := ⇑φ ⁻¹' setOfPred_sublevelLeft_subset X Y f t t' y2 y1
⊢ False

Tactic:
have mem_J2_iff (z : segment ℝ (y1 : F) y2) :
      z ∈ J2 ↔ sublevelLeft X f t z ⊆ sublevelLeft X f t' y2 := by
    simp [J2, setOfPred_sublevelLeft_subset, φ, Homeomorph.setCongr]

Goal state after:
E : Type u_1
F : Type u_2
β : Type u_3
inst✝¹¹ : LinearOrder β
X : Set E
Y : Set F
f : E → F → β
inst✝¹⁰ : TopologicalSpace E
inst✝⁹ : AddCommGroup E
inst✝⁸ : Module ℝ E
inst✝⁷ : IsTopologicalAddGroup E
inst✝⁶ : ContinuousSMul ℝ E
ne_X : X.Nonempty
kX : IsCompact X
hfy : ∀ y ∈ Y, LowerSemicontinuousOn (fun x ↦ f x y) X
hfy' : ∀ y ∈ Y, QuasiconvexOn ℝ X fun x ↦ f x y
inst✝⁵ : TopologicalSpace F
inst✝⁴ : AddCommGroup F
inst✝³ : Module ℝ F
cY : Convex ℝ Y
hfx : ∀ x ∈ X, UpperSemicontinuousOn (fun y ↦ f x y) Y
hfx' : ∀ x ∈ X, QuasiconcaveOn ℝ Y fun y ↦ f x y
inst✝² : DenselyOrdered β
inst✝¹ : IsTopologicalAddGroup F
inst✝ : ContinuousSMul ℝ F
t : β
hinfi_le : ∀ y0 ∈ Y, ∃ x ∈ X, f x y0 ≤ t
a : E
ha : a ∈ X
t' : β
htt' : t < t'
y1 y2 : { x // x ∈ Y }
ht : ∀ x ∈ X, t < max (f x ↑y1) (f x ↑y2)
ha' : IsMinOn (fun x ↦ max (f x ↑y1) (f x ↑y2)) X a
ht' : t' < max (f a ↑y1) (f a ↑y2)
J1 : Set ↑(segment ℝ ↑y1 ↑y2) := setOfPred_sublevelLeft_subset X Y f t t' y1 y2
mem_J1_iff : ∀ (z : ↑(segment ℝ ↑y1 ↑y2)), z ∈ J1 ↔ sublevelLeft X f t ↑z ⊆ sublevelLeft X f t' ↑y1
φ : ↑(segment ℝ ↑y1 ↑y2) ≃ₜ ↑(segment ℝ ↑y2 ↑y1) := Homeomorph.setCongr ⋯
J2 : Set ↑(segment ℝ ↑y1 ↑y2) := ⇑φ ⁻¹' setOfPred_sublevelLeft_subset X Y f t t' y2 y1
mem_J2_iff : ∀ (z : ↑(segment ℝ ↑y1 ↑y2)), z ∈ J2 ↔ sublevelLeft X f t ↑z ⊆ sublevelLeft X f t' ↑y2
⊢ False
Module: Mathlib.Topology.Spectral.ConstructibleTopology

Goal state before:
pp: case neg
X : Type u_1
inst✝⁴ : TopologicalSpace X
inst✝³ : CompactSpace X
inst✝² : QuasiSober X
inst✝¹ : PrespectralSpace X
inst✝ : QuasiSeparatedSpace X
𝔅 : Set (Set X) := constructibleTopologySubbasis X
𝒮 : Set (Set (Set X)) := {P | P ⊆ 𝔅 ∧ (∀ Q ⊆ P, Q.Finite → (⋂₀ Q).Nonempty) ∧ ⋂₀ P = ∅}
s : Set (Set X)
hs : s ∈ 𝒮
B : Set (Set X)
hsB : s ⊆ B
hB : Maximal (fun x ↦ x ∈ 𝒮) B
B' : Set (Set X) := {s | s ∈ B ∧ IsClosed[inst✝⁴] s}
Z : Set X := ⋂₀ B'
hZ_closed : IsClosed[inst✝⁴] Z
hZ_nonempty : Z.Nonempty
hZ_irred : ¬IsPreirreducible Z
Y₁ Y₂ : Set X
hY₁_cl : IsClosed[inst✝⁴] Y₁
hY₂_cl : IsClosed[inst✝⁴] Y₂
hc₁ : IsCompact Y₁ᶜ
hc₂ : IsCompact Y₂ᶜ
hsub : Z ⊆ Y₁ ∪ Y₂
x₁ : X
hx₁ : x₁ ∈ Z ∩ Y₁ᶜ
x₂ : X
hx₂ : x₂ ∈ Z ∩ Y₂ᶜ
hY₁ : Y₁ ∈ 𝔅
hY₂ : Y₂ ∈ 𝔅
hY₁_inter_B : Y₁ ∩ ⋂₀ B = ∅
hY₂_inter_B : Y₂ ∩ ⋂₀ B = ∅
hY₁B : insert Y₁ B ∉ 𝒮
⊢ False

Tactic:
have hY₂B : insert Y₂ B ∉ 𝒮 := by
      intro hY₂B
      grind [show insert Y₂ B ⊆ B from hB.le_of_ge hY₂B (Set.subset_insert Y₂ B)]

Goal state after:
case neg
X : Type u_1
inst✝⁴ : TopologicalSpace X
inst✝³ : CompactSpace X
inst✝² : QuasiSober X
inst✝¹ : PrespectralSpace X
inst✝ : QuasiSeparatedSpace X
𝔅 : Set (Set X) := constructibleTopologySubbasis X
𝒮 : Set (Set (Set X)) := {P | P ⊆ 𝔅 ∧ (∀ Q ⊆ P, Q.Finite → (⋂₀ Q).Nonempty) ∧ ⋂₀ P = ∅}
s : Set (Set X)
hs : s ∈ 𝒮
B : Set (Set X)
hsB : s ⊆ B
hB : Maximal (fun x ↦ x ∈ 𝒮) B
B' : Set (Set X) := {s | s ∈ B ∧ IsClosed[inst✝⁴] s}
Z : Set X := ⋂₀ B'
hZ_closed : IsClosed[inst✝⁴] Z
hZ_nonempty : Z.Nonempty
hZ_irred : ¬IsPreirreducible Z
Y₁ Y₂ : Set X
hY₁_cl : IsClosed[inst✝⁴] Y₁
hY₂_cl : IsClosed[inst✝⁴] Y₂
hc₁ : IsCompact Y₁ᶜ
hc₂ : IsCompact Y₂ᶜ
hsub : Z ⊆ Y₁ ∪ Y₂
x₁ : X
hx₁ : x₁ ∈ Z ∩ Y₁ᶜ
x₂ : X
hx₂ : x₂ ∈ Z ∩ Y₂ᶜ
hY₁ : Y₁ ∈ 𝔅
hY₂ : Y₂ ∈ 𝔅
hY₁_inter_B : Y₁ ∩ ⋂₀ B = ∅
hY₂_inter_B : Y₂ ∩ ⋂₀ B = ∅
hY₁B : insert Y₁ B ∉ 𝒮
hY₂B : insert Y₂ B ∉ 𝒮
⊢ False
Module: Mathlib.Topology.Sion

Goal state before:
pp: case a
E : Type u_1
F : Type u_2
β : Type u_3
inst✝¹¹ : LinearOrder β
X : Set E
Y : Set F
f : E → F → β
inst✝¹⁰ : TopologicalSpace E
inst✝⁹ : AddCommGroup E
inst✝⁸ : Module ℝ E
inst✝⁷ : IsTopologicalAddGroup E
inst✝⁶ : ContinuousSMul ℝ E
ne_X : X.Nonempty
kX : IsCompact X
hfy : ∀ y ∈ Y, LowerSemicontinuousOn (fun x ↦ f x y) X
hfy' : ∀ y ∈ Y, QuasiconvexOn ℝ X fun x ↦ f x y
inst✝⁵ : TopologicalSpace F
inst✝⁴ : AddCommGroup F
inst✝³ : Module ℝ F
cY : Convex ℝ Y
hfx : ∀ x ∈ X, UpperSemicontinuousOn (fun y ↦ f x y) Y
hfx' : ∀ x ∈ X, QuasiconcaveOn ℝ Y fun y ↦ f x y
inst✝² : DenselyOrdered β
inst✝¹ : IsTopologicalAddGroup F
inst✝ : ContinuousSMul ℝ F
cX : Convex ℝ X
sup_y : E → β
hsup_y : ∀ x ∈ X, IsLUB {x_1 | ∃ y ∈ Y, f x y = x_1} (sup_y x)
inf_sup : β
hinf_sup : IsGLB {x | ∃ x_1 ∈ X, sup_y x_1 = x} inf_sup
inf_x : F → β
hinf_x : ∀ y ∈ Y, IsGLB {x | ∃ x_1 ∈ X, f x_1 y = x} (inf_x y)
sup_inf : β
hsup_inf : IsLUB {x | ∃ y ∈ Y, inf_x y = x} sup_inf
⊢ sup_inf ≤ inf_sup

Tactic:
rw [le_isGLB_iff hinf_sup, mem_lowerBounds]
    rintro _ ⟨x, hx, rfl⟩
    rw [isLUB_le_iff hsup_inf, mem_upperBounds]
    rintro _ ⟨y, hy, rfl⟩
    trans f x y
    · exact (hinf_x y hy).1 ⟨x, hx, rfl⟩
    · exact (hsup_y x hx).1 ⟨y, hy, rfl⟩

Goal state after: