mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.MeasureTheory.Measure.Decomposition.Lebesgue

Goal state before:
pp: case pos
α : Type u_1
m : MeasurableSpace α
μ ν : Measure α
r : ℝ≥0
hr : ¬r = 0
hl : μ.HaveLebesgueDecomposition ν
⊢ (r • μ).singularPart ν = r • μ.singularPart ν

pp: case neg
α : Type u_1
m : MeasurableSpace α
μ ν : Measure α
r : ℝ≥0
hr : ¬r = 0
hl : ¬μ.HaveLebesgueDecomposition ν
⊢ (r • μ).singularPart ν = r • μ.singularPart ν

Tactic:
· refine (eq_singularPart ((measurable_rnDeriv μ ν).const_smul (r : ℝ≥0∞))
          (MutuallySingular.smul r (mutuallySingular_singularPart _ _)) ?_).symm
    rw [withDensity_smul _ (measurable_rnDeriv _ _), ← smul_add,
      ← haveLebesgueDecomposition_add μ ν, ENNReal.smul_def]

Goal state after:
case neg
α : Type u_1
m : MeasurableSpace α
μ ν : Measure α
r : ℝ≥0
hr : ¬r = 0
hl : ¬μ.HaveLebesgueDecomposition ν
⊢ (r • μ).singularPart ν = r • μ.singularPart ν
Module: Mathlib.MeasureTheory.Covering.Vitali

Goal state before:
pp: α : Type u_1
ι : Type u_2
inst✝⁴ : PseudoMetricSpace α
inst✝³ : MeasurableSpace α
inst✝² : OpensMeasurableSpace α
inst✝¹ : SecondCountableTopology α
μ : Measure α
inst✝ : IsLocallyFiniteMeasure μ
C : ℝ≥0
h : ∀ (x : α), ∃ᶠ (r : ℝ) in 𝓝[>] 0, μ (closedBall x (3 * r)) ≤ ↑C * μ (closedBall x r)
s : Set α
f : α → Set (Set α)
fsubset :
  ∀ x ∈ s,
    f x ⊆
      {a |
        IsClosed[PseudoMetricSpace.toUniformSpace.toTopologicalSpace] a ∧
          (interior a).Nonempty ∧ ∃ r, a ⊆ closedBall x r ∧ μ (closedBall x (3 * r)) ≤ ↑C * μ a}
ffine : ∀ x ∈ s, ∀ ε > 0, ∃ t ∈ f x, t ⊆ closedBall x ε
t : Set (ℝ × α × Set α) :=
  {p |
    p.2.2 ⊆ closedBall p.2.1 p.1 ∧
      μ (closedBall p.2.1 (3 * p.1)) ≤ ↑C * μ p.2.2 ∧
        (interior p.2.2).Nonempty ∧
          IsClosed[PseudoMetricSpace.toUniformSpace.toTopologicalSpace] p.2.2 ∧ p.2.2 ∈ f p.2.1 ∧ p.2.1 ∈ s}
x : α
xs : x ∈ s
ε : ℝ
⊢ ε > 0 → ∃ p ∈ t, p.1 ≤ ε ∧ p.2.1 = x

Tactic:
εpos

Goal state after:
α : Type u_1
ι : Type u_2
inst✝⁴ : PseudoMetricSpace α
inst✝³ : MeasurableSpace α
inst✝² : OpensMeasurableSpace α
inst✝¹ : SecondCountableTopology α
μ : Measure α
inst✝ : IsLocallyFiniteMeasure μ
C : ℝ≥0
h : ∀ (x : α), ∃ᶠ (r : ℝ) in 𝓝[>] 0, μ (closedBall x (3 * r)) ≤ ↑C * μ (closedBall x r)
s : Set α
f : α → Set (Set α)
fsubset :
  ∀ x ∈ s,
    f x ⊆
      {a |
        IsClosed[PseudoMetricSpace.toUniformSpace.toTopologicalSpace] a ∧
          (interior a).Nonempty ∧ ∃ r, a ⊆ closedBall x r ∧ μ (closedBall x (3 * r)) ≤ ↑C * μ a}
ffine : ∀ x ∈ s, ∀ ε > 0, ∃ t ∈ f x, t ⊆ closedBall x ε
t : Set (ℝ × α × Set α) :=
  {p |
    p.2.2 ⊆ closedBall p.2.1 p.1 ∧
      μ (closedBall p.2.1 (3 * p.1)) ≤ ↑C * μ p.2.2 ∧
        (interior p.2.2).Nonempty ∧
          IsClosed[PseudoMetricSpace.toUniformSpace.toTopologicalSpace] p.2.2 ∧ p.2.2 ∈ f p.2.1 ∧ p.2.1 ∈ s}
x : α
xs : x ∈ s
ε : ℝ
εpos : ε > 0
⊢ ∃ p ∈ t, p.1 ≤ ε ∧ p.2.1 = x
Module: Mathlib.MeasureTheory.Covering.Differentiation

Goal state before:
pp: α : Type u_1
inst✝¹ : PseudoMetricSpace α
m0 : MeasurableSpace α
μ : Measure α
v : VitaliFamily μ
inst✝ : SecondCountableTopology α
s : Set α := {x | ¬∀ᶠ (a : Set α) in v.filterAt x, 0 < μ a}
hs : s = {x | ∃ᶠ (x : Set α) in v.filterAt x, μ x = 0}
f : α → Set (Set α) := fun x ↦ {a | μ a = 0}
x : α
hx : x ∈ s
ε : ℝ
⊢ ε > 0 → ∃ t ∈ v.setsAt x ∩ f x, t ⊆ closedBall x ε

Tactic:
εpos

Goal state after:
α : Type u_1
inst✝¹ : PseudoMetricSpace α
m0 : MeasurableSpace α
μ : Measure α
v : VitaliFamily μ
inst✝ : SecondCountableTopology α
s : Set α := {x | ¬∀ᶠ (a : Set α) in v.filterAt x, 0 < μ a}
hs : s = {x | ∃ᶠ (x : Set α) in v.filterAt x, μ x = 0}
f : α → Set (Set α) := fun x ↦ {a | μ a = 0}
x : α
hx : x ∈ s
ε : ℝ
εpos : ε > 0
⊢ ∃ t ∈ v.setsAt x ∩ f x, t ⊆ closedBall x ε
Module: Mathlib.MeasureTheory.Covering.Differentiation

Goal state before:
pp: α : Type u_1
inst✝⁴ : PseudoMetricSpace α
m0 : MeasurableSpace α
μ : Measure α
v : VitaliFamily μ
inst✝³ : SecondCountableTopology α
inst✝² : BorelSpace α
inst✝¹ : IsLocallyFiniteMeasure μ
ρ : Measure α
inst✝ : IsLocallyFiniteMeasure ρ
hρ : ρ ⟂ₘ μ
ε : ℝ≥0
⊢ ε > 0 → ∀ᵐ (x : α) ∂μ, ∀ᶠ (a : Set α) in v.filterAt x, ρ a < ↑ε * μ a

Tactic:
εpos

Goal state after:
α : Type u_1
inst✝⁴ : PseudoMetricSpace α
m0 : MeasurableSpace α
μ : Measure α
v : VitaliFamily μ
inst✝³ : SecondCountableTopology α
inst✝² : BorelSpace α
inst✝¹ : IsLocallyFiniteMeasure μ
ρ : Measure α
inst✝ : IsLocallyFiniteMeasure ρ
hρ : ρ ⟂ₘ μ
ε : ℝ≥0
εpos : ε > 0
⊢ ∀ᵐ (x : α) ∂μ, ∀ᶠ (a : Set α) in v.filterAt x, ρ a < ↑ε * μ a
Module: Mathlib.MeasureTheory.Covering.Vitali

Goal state before:
pp: α : Type u_1
ι : Type u_2
inst✝⁴ : PseudoMetricSpace α
inst✝³ : MeasurableSpace α
inst✝² : OpensMeasurableSpace α
inst✝¹ : SecondCountableTopology α
μ : Measure α
inst✝ : IsLocallyFiniteMeasure μ
C : ℝ≥0
h : ∀ (x : α), ∃ᶠ (r : ℝ) in 𝓝[>] 0, μ (closedBall x (3 * r)) ≤ ↑C * μ (closedBall x r)
s : Set α
f : α → Set (Set α)
fsubset :
  ∀ x ∈ s,
    f x ⊆
      {a |
        IsClosed[PseudoMetricSpace.toUniformSpace.toTopologicalSpace] a ∧
          (interior a).Nonempty ∧ ∃ r, a ⊆ closedBall x r ∧ μ (closedBall x (3 * r)) ≤ ↑C * μ a}
ffine : ∀ x ∈ s, ∀ ε > 0, ∃ t ∈ f x, t ⊆ closedBall x ε
t : Set (ℝ × α × Set α) :=
  {p |
    p.2.2 ⊆ closedBall p.2.1 p.1 ∧
      μ (closedBall p.2.1 (3 * p.1)) ≤ ↑C * μ p.2.2 ∧
        (interior p.2.2).Nonempty ∧
          IsClosed[PseudoMetricSpace.toUniformSpace.toTopologicalSpace] p.2.2 ∧ p.2.2 ∈ f p.2.1 ∧ p.2.1 ∈ s}
A : ∀ x ∈ s, ∀ ε > 0, ∃ p ∈ t, p.1 ≤ ε ∧ p.2.1 = x
⊢ ∃ t, (∀ p ∈ t, p.1 ∈ s) ∧ (t.PairwiseDisjoint fun p ↦ p.2) ∧ (∀ p ∈ t, p.2 ∈ f p.1) ∧ μ (s \ ⋃ p ∈ t, p.2) = 0

Tactic:
rcases exists_disjoint_covering_ae μ s t C (fun p => p.1) (fun p => p.2.1) (fun p => p.2.2)
        (fun p hp => hp.1) (fun p hp => hp.2.1) (fun p hp => hp.2.2.1) (fun p hp => hp.2.2.2.1) A
      with ⟨t', t't, _, t'_disj, μt'⟩

Goal state after:
α : Type u_1
ι : Type u_2
inst✝⁴ : PseudoMetricSpace α
inst✝³ : MeasurableSpace α
inst✝² : OpensMeasurableSpace α
inst✝¹ : SecondCountableTopology α
μ : Measure α
inst✝ : IsLocallyFiniteMeasure μ
C : ℝ≥0
h : ∀ (x : α), ∃ᶠ (r : ℝ) in 𝓝[>] 0, μ (closedBall x (3 * r)) ≤ ↑C * μ (closedBall x r)
s : Set α
f : α → Set (Set α)
fsubset :
  ∀ x ∈ s,
    f x ⊆
      {a |
        IsClosed[PseudoMetricSpace.toUniformSpace.toTopologicalSpace] a ∧
          (interior a).Nonempty ∧ ∃ r, a ⊆ closedBall x r ∧ μ (closedBall x (3 * r)) ≤ ↑C * μ a}
ffine : ∀ x ∈ s, ∀ ε > 0, ∃ t ∈ f x, t ⊆ closedBall x ε
t : Set (ℝ × α × Set α) :=
  {p |
    p.2.2 ⊆ closedBall p.2.1 p.1 ∧
      μ (closedBall p.2.1 (3 * p.1)) ≤ ↑C * μ p.2.2 ∧
        (interior p.2.2).Nonempty ∧
          IsClosed[PseudoMetricSpace.toUniformSpace.toTopologicalSpace] p.2.2 ∧ p.2.2 ∈ f p.2.1 ∧ p.2.1 ∈ s}
A : ∀ x ∈ s, ∀ ε > 0, ∃ p ∈ t, p.1 ≤ ε ∧ p.2.1 = x
t' : Set (ℝ × α × Set α)
t't : t' ⊆ t
left✝ : t'.Countable
t'_disj : t'.PairwiseDisjoint fun p ↦ p.2.2
μt' : μ (s \ ⋃ a ∈ t', a.2.2) = 0
⊢ ∃ t, (∀ p ∈ t, p.1 ∈ s) ∧ (t.PairwiseDisjoint fun p ↦ p.2) ∧ (∀ p ∈ t, p.2 ∈ f p.1) ∧ μ (s \ ⋃ p ∈ t, p.2) = 0
Module: Mathlib.MeasureTheory.Measure.Decomposition.Lebesgue

Goal state before:
pp: α : Type u_1
m : MeasurableSpace α
μ ν : Measure α
inst✝¹ : IsFiniteMeasure μ
inst✝ : IsFiniteMeasure ν
h : ¬μ ⟂ₘ ν
h_decomp :
  ∀ (n : ℕ),
    ∃ s,
      MeasurableSet s ∧
        (∀ (t : Set α), MeasurableSet t → ((1 / (↑n + 1)) • ν) (t ∩ s) ≤ μ (t ∩ s)) ∧
          ∀ (t : Set α), MeasurableSet t → μ (t ∩ sᶜ) ≤ ((1 / (↑n + 1)) • ν) (t ∩ sᶜ)
⊢ ∃ ε, 0 < ε ∧ ∃ E, MeasurableSet E ∧ 0 < ν E ∧ ∀ (A : Set α), MeasurableSet A → ↑ε * ν (A ∩ E) ≤ μ (A ∩ E)

Tactic:
choose f hf₁ hf₂ hf₃ using h_decomp

Goal state after:
α : Type u_1
m : MeasurableSpace α
μ ν : Measure α
inst✝¹ : IsFiniteMeasure μ
inst✝ : IsFiniteMeasure ν
h : ¬μ ⟂ₘ ν
f : ℕ → Set α
hf₁ : ∀ (n : ℕ), MeasurableSet (f n)
hf₂ : ∀ (n : ℕ) (t : Set α), MeasurableSet t → ((1 / (↑n + 1)) • ν) (t ∩ f n) ≤ μ (t ∩ f n)
hf₃ : ∀ (n : ℕ) (t : Set α), MeasurableSet t → μ (t ∩ (f n)ᶜ) ≤ ((1 / (↑n + 1)) • ν) (t ∩ (f n)ᶜ)
⊢ ∃ ε, 0 < ε ∧ ∃ E, MeasurableSet E ∧ 0 < ν E ∧ ∀ (A : Set α), MeasurableSet A → ↑ε * ν (A ∩ E) ≤ μ (A ∩ E)
Module: Mathlib.MeasureTheory.Covering.Vitali

Goal state before:
pp: case refine_2
α : Type u_1
ι : Type u_2
inst✝⁴ : PseudoMetricSpace α
inst✝³ : MeasurableSpace α
inst✝² : OpensMeasurableSpace α
inst✝¹ : SecondCountableTopology α
μ : Measure α
inst✝ : IsLocallyFiniteMeasure μ
C : ℝ≥0
h : ∀ (x : α), ∃ᶠ (r : ℝ) in 𝓝[>] 0, μ (closedBall x (3 * r)) ≤ ↑C * μ (closedBall x r)
s : Set α
f : α → Set (Set α)
fsubset :
  ∀ x ∈ s,
    f x ⊆
      {a |
        IsClosed[PseudoMetricSpace.toUniformSpace.toTopologicalSpace] a ∧
          (interior a).Nonempty ∧ ∃ r, a ⊆ closedBall x r ∧ μ (closedBall x (3 * r)) ≤ ↑C * μ a}
ffine : ∀ x ∈ s, ∀ ε > 0, ∃ t ∈ f x, t ⊆ closedBall x ε
t : Set (ℝ × α × Set α) :=
  {p |
    p.2.2 ⊆ closedBall p.2.1 p.1 ∧
      μ (closedBall p.2.1 (3 * p.1)) ≤ ↑C * μ p.2.2 ∧
        (interior p.2.2).Nonempty ∧
          IsClosed[PseudoMetricSpace.toUniformSpace.toTopologicalSpace] p.2.2 ∧ p.2.2 ∈ f p.2.1 ∧ p.2.1 ∈ s}
A : ∀ x ∈ s, ∀ ε > 0, ∃ p ∈ t, p.1 ≤ ε ∧ p.2.1 = x
t' : Set (ℝ × α × Set α)
t't : t' ⊆ t
left✝ : t'.Countable
t'_disj : t'.PairwiseDisjoint fun p ↦ p.2.2
μt' : μ (s \ ⋃ a ∈ t', a.2.2) = 0
⊢ ((fun p ↦ p.2) '' t').PairwiseDisjoint fun p ↦ p.2

Tactic:
rintro p ⟨q, hq, rfl⟩ p' ⟨q', hq', rfl⟩ hqq'

Goal state after:
case refine_2
α : Type u_1
ι : Type u_2
inst✝⁴ : PseudoMetricSpace α
inst✝³ : MeasurableSpace α
inst✝² : OpensMeasurableSpace α
inst✝¹ : SecondCountableTopology α
μ : Measure α
inst✝ : IsLocallyFiniteMeasure μ
C : ℝ≥0
h : ∀ (x : α), ∃ᶠ (r : ℝ) in 𝓝[>] 0, μ (closedBall x (3 * r)) ≤ ↑C * μ (closedBall x r)
s : Set α
f : α → Set (Set α)
fsubset :
  ∀ x ∈ s,
    f x ⊆
      {a |
        IsClosed[PseudoMetricSpace.toUniformSpace.toTopologicalSpace] a ∧
          (interior a).Nonempty ∧ ∃ r, a ⊆ closedBall x r ∧ μ (closedBall x (3 * r)) ≤ ↑C * μ a}
ffine : ∀ x ∈ s, ∀ ε > 0, ∃ t ∈ f x, t ⊆ closedBall x ε
t : Set (ℝ × α × Set α) :=
  {p |
    p.2.2 ⊆ closedBall p.2.1 p.1 ∧
      μ (closedBall p.2.1 (3 * p.1)) ≤ ↑C * μ p.2.2 ∧
        (interior p.2.2).Nonempty ∧
          IsClosed[PseudoMetricSpace.toUniformSpace.toTopologicalSpace] p.2.2 ∧ p.2.2 ∈ f p.2.1 ∧ p.2.1 ∈ s}
A : ∀ x ∈ s, ∀ ε > 0, ∃ p ∈ t, p.1 ≤ ε ∧ p.2.1 = x
t' : Set (ℝ × α × Set α)
t't : t' ⊆ t
left✝ : t'.Countable
t'_disj : t'.PairwiseDisjoint fun p ↦ p.2.2
μt' : μ (s \ ⋃ a ∈ t', a.2.2) = 0
q : ℝ × α × Set α
hq : q ∈ t'
q' : ℝ × α × Set α
hq' : q' ∈ t'
hqq' : (fun p ↦ p.2) q ≠ (fun p ↦ p.2) q'
⊢ Function.onFun Disjoint (fun p ↦ p.2) ((fun p ↦ p.2) q) ((fun p ↦ p.2) q')
Module: Mathlib.MeasureTheory.Covering.OneDim

Goal state before:
pp: case refine_2
x ε : ℝ
⊢ ε > 0 → ∀ᶠ (i : ℝ) in 𝓝[>] x, Icc x i ⊆ Metric.closedBall x ε

Tactic:
εpos

Goal state after:
case refine_2
x ε : ℝ
εpos : ε > 0
⊢ ∀ᶠ (i : ℝ) in 𝓝[>] x, Icc x i ⊆ Metric.closedBall x ε
Module: Mathlib.MeasureTheory.Covering.OneDim

Goal state before:
pp: case refine_2
x ε : ℝ
⊢ ε > 0 → ∀ᶠ (i : ℝ) in 𝓝[<] x, Icc i x ⊆ Metric.closedBall x ε

Tactic:
εpos

Goal state after:
case refine_2
x ε : ℝ
εpos : ε > 0
⊢ ∀ᶠ (i : ℝ) in 𝓝[<] x, Icc i x ⊆ Metric.closedBall x ε
Module: Mathlib.Topology.EMetricSpace.VariationOnFromTo

Goal state before:
pp: α : Type u_1
inst✝¹ : LinearOrder α
E : Type u_2
inst✝ : PseudoEMetricSpace E
f : α → E
s : Set α
hf : LocallyBoundedVariationOn f s
a b : α
ha : a ∈ s
hb : b ∈ s
ba : b ≤ a
⊢ -(eVariationOn f (s ∩ Icc b a)).toReal = 0 ↔
    ∀ ⦃x : α⦄, x ∈ s ∩ Icc b a → ∀ ⦃y : α⦄, y ∈ s ∩ Icc b a → edist (f x) (f y) = 0

Tactic:
neg_eq_zero,

Goal state after:
α : Type u_1
inst✝¹ : LinearOrder α
E : Type u_2
inst✝ : PseudoEMetricSpace E
f : α → E
s : Set α
hf : LocallyBoundedVariationOn f s
a b : α
ha : a ∈ s
hb : b ∈ s
ba : b ≤ a
⊢ (eVariationOn f (s ∩ Icc b a)).toReal = 0 ↔
    ∀ ⦃x : α⦄, x ∈ s ∩ Icc b a → ∀ ⦃y : α⦄, y ∈ s ∩ Icc b a → edist (f x) (f y) = 0
Module: Mathlib.Topology.EMetricSpace.VariationOnFromTo

Goal state before:
pp: α : Type u_1
inst✝ : LinearOrder α
f : α → ℝ
s : Set α
h : LocallyBoundedVariationOn f s
⊢ ∃ p q, MonotoneOn p s ∧ MonotoneOn q s ∧ f = p - q

Tactic:
rcases h.exists_monotoneOn_sub_monotoneOn' with ⟨p, q, hp, hq, h'f, -⟩
  exact ⟨p, q, hp, hq, h'f⟩

Goal state after:
Module: Mathlib.Topology.EMetricSpace.BoundedVariation

Goal state before:
pp: α : Type u_1
inst✝¹ : LinearOrder α
E : Type u_2
inst✝ : PseudoEMetricSpace E
f : α → E
s : Set α
a b c : α
hab : a ≤ b
hbc : b ≤ c
hb : b ∈ s
⊢ eVariationOn f (s ∩ Icc a b) + eVariationOn f (s ∩ Icc b c) = eVariationOn f (s ∩ Icc a c)

Tactic:
by
  have A : IsGreatest (s ∩ Icc a b) b :=
    ⟨⟨hb, hab, le_rfl⟩, inter_subset_right.trans Icc_subset_Iic_self⟩
  have B : IsLeast (s ∩ Icc b c) b :=
    ⟨⟨hb, le_rfl, hbc⟩, inter_subset_right.trans Icc_subset_Ici_self⟩
  rw [← eVariationOn.union f A B, ← inter_union_distrib_left, Icc_union_Icc_eq_Icc hab hbc]

Goal state after:
Module: Mathlib.Topology.EMetricSpace.BoundedVariation

Goal state before:
pp: case refine_1
α : Type u_1
inst✝³ : LinearOrder α
E : Type u_2
inst✝² : PseudoEMetricSpace E
inst✝¹ : TopologicalSpace α
inst✝ : OrderTopology α
f : α → E
s : Set α
a : α
l : E
h : (𝓝[s ∩ Iio a] a).NeBot
ha : a ∈ s
h'f : Tendsto f (𝓝[s ∩ Iio a] a) (𝓝 l)
⊢ eVariationOn f (s ∩ Iic a) ≤ eVariationOn f (s ∩ Iio a) + edist (f a) l

pp: case refine_2
α : Type u_1
inst✝³ : LinearOrder α
E : Type u_2
inst✝² : PseudoEMetricSpace E
inst✝¹ : TopologicalSpace α
inst✝ : OrderTopology α
f : α → E
s : Set α
a : α
l : E
h : (𝓝[s ∩ Iio a] a).NeBot
ha : a ∈ s
h'f : Tendsto f (𝓝[s ∩ Iio a] a) (𝓝 l)
⊢ eVariationOn f (s ∩ Iio a) + edist (f a) l ≤ eVariationOn f (s ∩ Iic a)

Tactic:
· rw [eVariationOn_eq_strictMonoOn]
    apply iSup_le
    rintro ⟨n, u, u_mono, u_mem⟩
    have : u n ≤ a := (u_mem n (by simp)).2
    rcases this.eq_or_lt with hn | hn; swap
    · exact (sum_le_of_monotoneOn_Iic u_mono.monotoneOn (by grind [StrictMonoOn])).trans le_self_add
    cases n with
    | zero => simp
    | succ n =>
      have : Tendsto (fun y ↦ eVariationOn f (s ∩ Iio a) + edist (f a) (f y)) (𝓝[s ∩ Iio a] a)
          (𝓝 (eVariationOn f (s ∩ Iio a) + edist (f a) l)) :=
        (Tendsto.edist tendsto_const_nhds h'f).const_add _
      apply ge_of_tendsto this
      have : s ∩ Ioo (u n) a ∈ 𝓝[s ∩ Iio a] a :=
        inter_mem_nhdsWithin_inter self_mem_nhdsWithin (Ioo_mem_nhdsLT (by grind [StrictMonoOn]))
      filter_upwards [this] with y hy
      let v i := if i ≤ n then u i else if i = n + 1 then y else a
      have A : ∑ i ∈ Finset.range (n + 1), edist (f (u (i + 1))) (f (u i))
          ≤ ∑ i ∈ Finset.range (n + 2), edist (f (v (i + 1))) (f (v i)) := by
        simp only [Finset.sum_range_succ, add_assoc]
        gcongr with i h
        · grind
        · grw [add_comm (edist _ _), ← edist_triangle]
          grind
      have B : ∑ i ∈ Finset.range (n + 2), edist (f (v (i + 1))) (f (v i)) ≤
            eVariationOn f (s ∩ Iio a) + edist (f a) (f y) := by
        rw [Finset.sum_range_succ]
        gcongr
        · apply sum_le_of_monotoneOn_Iic <;> grind [MonotoneOn, StrictMonoOn]
        · grind
      exact A.trans B

Goal state after:
case refine_2
α : Type u_1
inst✝³ : LinearOrder α
E : Type u_2
inst✝² : PseudoEMetricSpace E
inst✝¹ : TopologicalSpace α
inst✝ : OrderTopology α
f : α → E
s : Set α
a : α
l : E
h : (𝓝[s ∩ Iio a] a).NeBot
ha : a ∈ s
h'f : Tendsto f (𝓝[s ∩ Iio a] a) (𝓝 l)
⊢ eVariationOn f (s ∩ Iio a) + edist (f a) l ≤ eVariationOn f (s ∩ Iic a)
Module: Mathlib.Analysis.CStarAlgebra.ContinuousFunctionalCalculus.Unital

Goal state before:
pp: R : Type u_1
A : Type u_2
p : A → Prop
inst✝⁸ : CommSemiring R
inst✝⁷ : StarRing R
inst✝⁶ : MetricSpace R
inst✝⁵ : IsTopologicalSemiring R
inst✝⁴ : ContinuousStar R
inst✝³ : TopologicalSpace A
inst✝² : Ring A
inst✝¹ : StarRing A
inst✝ : Algebra R A
instCFC : ContinuousFunctionalCalculus R A p
r : R
f : R → R
h₁ : ContinuousOn f (spectrum R ((algebraMap R A) r))
⊢ (cfcHom ⋯) { toFun := (spectrum R ((algebraMap R A) r)).domRestrict f, continuous_toFun := ⋯ } =
    (algebraMap R A) (f r)

Tactic:
← AlgHomClass.commutes (cfcHom (p := p) (cfc_predicate_algebraMap r)) (f r)

Goal state after:
R : Type u_1
A : Type u_2
p : A → Prop
inst✝⁸ : CommSemiring R
inst✝⁷ : StarRing R
inst✝⁶ : MetricSpace R
inst✝⁵ : IsTopologicalSemiring R
inst✝⁴ : ContinuousStar R
inst✝³ : TopologicalSpace A
inst✝² : Ring A
inst✝¹ : StarRing A
inst✝ : Algebra R A
instCFC : ContinuousFunctionalCalculus R A p
r : R
f : R → R
h₁ : ContinuousOn f (spectrum R ((algebraMap R A) r))
⊢ (cfcHom ⋯) { toFun := (spectrum R ((algebraMap R A) r)).domRestrict f, continuous_toFun := ⋯ } =
    (cfcHom ⋯) ((algebraMap R C(↑(spectrum R ((algebraMap R A) r)), R)) (f r))
Module: Mathlib.Analysis.CStarAlgebra.ContinuousFunctionalCalculus.Unital

Goal state before:
pp: R : Type u_1
A : Type u_2
p : A → Prop
inst✝¹⁰ : Semifield R
inst✝⁹ : StarRing R
inst✝⁸ : MetricSpace R
inst✝⁷ : IsTopologicalSemiring R
inst✝⁶ : ContinuousStar R
inst✝⁵ : TopologicalSpace A
inst✝⁴ : Ring A
inst✝³ : StarRing A
inst✝² : Algebra R A
inst✝¹ : ContinuousFunctionalCalculus R A p
inst✝ : ContinuousInv₀ R
f g : R → R
a : A
hg' : ∀ x ∈ spectrum R a, g x ≠ 0
hf : ContinuousOn f (spectrum R a)
hg : ContinuousOn g (spectrum R a)
ha : p a
⊢ cfc (fun x ↦ f x / g x) a = cfc f a * (cfc g a)⁻¹ʳ

Tactic:
by
  simp only [div_eq_mul_inv]
  rw [cfc_mul .., cfc_inv g a hg']

Goal state after:
Module: Mathlib.Analysis.CStarAlgebra.ContinuousFunctionalCalculus.Unital

Goal state before:
pp: case pos
R : Type u_1
A : Type u_2
p : A → Prop
inst✝⁹ : CommRing R
inst✝⁸ : StarRing R
inst✝⁷ : MetricSpace R
inst✝⁶ : IsTopologicalRing R
inst✝⁵ : ContinuousStar R
inst✝⁴ : TopologicalSpace A
inst✝³ : Ring A
inst✝² : StarRing A
inst✝¹ : Algebra R A
inst✝ : ContinuousFunctionalCalculus R A p
f g : R → R
a : A
hf : ContinuousOn f (spectrum R a)
hg : ContinuousOn g (spectrum R a)
ha : p a
⊢ cfc (fun x ↦ f x - g x) a = cfc f a - cfc g a

pp: case neg
R : Type u_1
A : Type u_2
p : A → Prop
inst✝⁹ : CommRing R
inst✝⁸ : StarRing R
inst✝⁷ : MetricSpace R
inst✝⁶ : IsTopologicalRing R
inst✝⁵ : ContinuousStar R
inst✝⁴ : TopologicalSpace A
inst✝³ : Ring A
inst✝² : StarRing A
inst✝¹ : Algebra R A
inst✝ : ContinuousFunctionalCalculus R A p
f g : R → R
a : A
hf : ContinuousOn f (spectrum R a)
hg : ContinuousOn g (spectrum R a)
ha : ¬p a
⊢ cfc (fun x ↦ f x - g x) a = cfc f a - cfc g a

Tactic:
· rw [cfc_apply f a, cfc_apply g a, ← map_sub, cfc_apply ..]
    congr

Goal state after:
case neg
R : Type u_1
A : Type u_2
p : A → Prop
inst✝⁹ : CommRing R
inst✝⁸ : StarRing R
inst✝⁷ : MetricSpace R
inst✝⁶ : IsTopologicalRing R
inst✝⁵ : ContinuousStar R
inst✝⁴ : TopologicalSpace A
inst✝³ : Ring A
inst✝² : StarRing A
inst✝¹ : Algebra R A
inst✝ : ContinuousFunctionalCalculus R A p
f g : R → R
a : A
hf : ContinuousOn f (spectrum R a)
hg : ContinuousOn g (spectrum R a)
ha : ¬p a
⊢ cfc (fun x ↦ f x - g x) a = cfc f a - cfc g a
Module: Mathlib.Analysis.CStarAlgebra.ContinuousFunctionalCalculus.Restrict

Goal state before:
pp: R : Type u_1
S : Type u_2
A : Type u_3
p q : A → Prop
inst✝²⁵ : Semifield R
inst✝²⁴ : StarRing R
inst✝²³ : MetricSpace R
inst✝²² : IsTopologicalSemiring R
inst✝²¹ : ContinuousStar R
inst✝²⁰ : Field S
inst✝¹⁹ : StarRing S
inst✝¹⁸ : MetricSpace S
inst✝¹⁷ : IsTopologicalRing S
inst✝¹⁶ : ContinuousStar S
inst✝¹⁵ : NonUnitalRing A
inst✝¹⁴ : StarRing A
inst✝¹³ : Module S A
inst✝¹² : IsScalarTower S A A
inst✝¹¹ : SMulCommClass S A A
inst✝¹⁰ : Algebra R S
inst✝⁹ : Module R A
inst✝⁸ : IsScalarTower R S A
inst✝⁷ : StarModule R S
inst✝⁶ : ContinuousSMul R S
inst✝⁵ : TopologicalSpace A
inst✝⁴ : NonUnitalContinuousFunctionalCalculus S A q
inst✝³ : IsScalarTower R A A
inst✝² : SMulCommClass R A A
inst✝¹ : NonUnitalContinuousFunctionalCalculus R A p
inst✝ : UniqueHom R A
f : C(S, R)
halg : IsClosedEmbedding ⇑(algebraMap R S)
a : A
hpa : p a
hqa : q a
h : QuasispectrumRestricts a ⇑f
g : R → R
⊢ cfcₙ g a = cfcₙ (fun x ↦ (algebraMap R S) (g (f x))) a

Tactic:
by
  by_cases hg : ContinuousOn g (σₙ R a) ∧ g 0 = 0
  · obtain ⟨hg, hg0⟩ := hg
    rw [cfcₙ_apply g a, cfcₙHom_eq_restrict f hpa hqa h, nonUnitalStarAlgHom_apply,
      cfcₙHom_eq_cfcₙ_extend 0]
    apply cfcₙ_congr fun x hx ↦ ?_
    lift x to σₙ S a using hx
    simp
  · simp only [not_and_or] at hg
    obtain (hg | hg) := hg
    · have : ¬ ContinuousOn (fun x ↦ algebraMap R S (g (f x)) : S → S) (σₙ S a) := by
        refine fun hg' ↦ hg ?_
        rw [halg.isEmbedding.continuousOn_iff]
        simpa [halg.isEmbedding.continuousOn_iff, Function.comp_def, h.left_inv _] using
          hg'.comp halg.isEmbedding.continuous.continuousOn
          (fun _ : R ↦ quasispectrum.algebraMap_mem S)
      rw [cfcₙ_apply_of_not_continuousOn a hg, cfcₙ_apply_of_not_continuousOn a this]
    · rw [cfcₙ_apply_of_not_map_zero a hg, cfcₙ_apply_of_not_map_zero a (by simpa [h.map_zero])]

Goal state after:
Module: Mathlib.RingTheory.Polynomial.Bernstein

Goal state before:
pp: case pos
R : Type u_1
inst✝ : CommRing R
n ν : ℕ
h : ν ≤ n
⊢ eval 0 ((⇑derivative)^[ν] (bernsteinPolynomial R n ν)) = eval (↑(n - (ν - 1))) (ascPochhammer R ν)

Tactic:
induction ν generalizing n with

Goal state after:
Module: Mathlib.Topology.ContinuousMap.Polynomial

Goal state before:
pp: case mp
a b : ℝ
h : a < b
f : C(↑(Set.Icc a b), ℝ)
p : ℝ[X]
w : ↑(toContinuousMapOnAlgHom I) p = ↑(compRightAlgHom ℝ ℝ ↑(iccHomeoI a b h).symm) f
⊢ f ∈ polynomialFunctions (Set.Icc a b)

Tactic:
DFunLike.ext_iff

Goal state after:
case mp
a b : ℝ
h : a < b
f : C(↑(Set.Icc a b), ℝ)
p : ℝ[X]
w : ∀ (x : ↑I), (↑(toContinuousMapOnAlgHom I) p) x = (↑(compRightAlgHom ℝ ℝ ↑(iccHomeoI a b h).symm) f) x
⊢ f ∈ polynomialFunctions (Set.Icc a b)
Module: Mathlib.RingTheory.Polynomial.Bernstein

Goal state before:
pp: n k : ℕ
h : k ≤ n
p : ℚ[X]
m : p ∈ span ℚ (Set.range fun k_1 ↦ bernsteinPolynomial ℚ n ↑k_1)
⊢ eval 1 ((⇑derivative)^[n - k] p) ≠ eval 1 ((⇑derivative)^[n - k] (bernsteinPolynomial ℚ n k))

Tactic:
suffices (Polynomial.derivative^[n - k] p).eval 1 = 0 by
        rw [this]
        exact (iterate_derivative_at_1_ne_zero ℚ n k h).symm

Goal state after:
n k : ℕ
h : k ≤ n
p : ℚ[X]
m : p ∈ span ℚ (Set.range fun k_1 ↦ bernsteinPolynomial ℚ n ↑k_1)
⊢ eval 1 ((⇑derivative)^[n - k] p) = 0
Module: Mathlib.Topology.ContinuousMap.Weierstrass

Goal state before:
pp: case inl
a b : ℝ
h : a < b
W : C(↑(Set.Icc a b), ℝ) →ₐ[ℝ] C(↑I, ℝ) := compRightAlgHom ℝ ℝ ↑(iccHomeoI a b h).symm
W' : C(↑(Set.Icc a b), ℝ) ≃ₜ C(↑I, ℝ) := (iccHomeoI a b h).arrowCongr (Homeomorph.refl ℝ)
w : ⇑W = ⇑W'
⊢ (polynomialFunctions (Set.Icc a b)).topologicalClosure = ⊤

Tactic:
have p := polynomialFunctions_closure_eq_top'

Goal state after:
case inl
a b : ℝ
h : a < b
W : C(↑(Set.Icc a b), ℝ) →ₐ[ℝ] C(↑I, ℝ) := compRightAlgHom ℝ ℝ ↑(iccHomeoI a b h).symm
W' : C(↑(Set.Icc a b), ℝ) ≃ₜ C(↑I, ℝ) := (iccHomeoI a b h).arrowCongr (Homeomorph.refl ℝ)
w : ⇑W = ⇑W'
p : (polynomialFunctions I).topologicalClosure = ⊤
⊢ (polynomialFunctions (Set.Icc a b)).topologicalClosure = ⊤
Module: Mathlib.Topology.ContinuousMap.StoneWeierstrass

Goal state before:
pp: 𝕜 : Type u_1
X : Type u_2
inst✝² : RCLike 𝕜
inst✝¹ : TopologicalSpace X
inst✝ : CompactSpace X
A : StarSubalgebra 𝕜 C(X, 𝕜)
hA : A.SeparatesPoints
I : C(X, ℝ) →L[ℝ] C(X, 𝕜) := ContinuousLinearMap.compLeftContinuous ℝ X ofRealCLM
A₀ : Submodule ℝ C(X, ℝ) := Submodule.comap (↑I) (Submodule.restrictScalars ℝ (Subalgebra.toSubmodule A.toSubalgebra))
⊢ (↑I).range ≤ (Submodule.restrictScalars ℝ (Subalgebra.toSubmodule A.toSubalgebra)).topologicalClosure

Tactic:
have SW : A₀.topologicalClosure = ⊤ :=
      haveI := subalgebra_topologicalClosure_eq_top_of_separatesPoints _ hA.rclike_to_real
      congr_arg Subalgebra.toSubmodule this

Goal state after:
𝕜 : Type u_1
X : Type u_2
inst✝² : RCLike 𝕜
inst✝¹ : TopologicalSpace X
inst✝ : CompactSpace X
A : StarSubalgebra 𝕜 C(X, 𝕜)
hA : A.SeparatesPoints
I : C(X, ℝ) →L[ℝ] C(X, 𝕜) := ContinuousLinearMap.compLeftContinuous ℝ X ofRealCLM
A₀ : Submodule ℝ C(X, ℝ) := Submodule.comap (↑I) (Submodule.restrictScalars ℝ (Subalgebra.toSubmodule A.toSubalgebra))
SW : A₀.topologicalClosure = ⊤
⊢ (↑I).range ≤ (Submodule.restrictScalars ℝ (Subalgebra.toSubmodule A.toSubalgebra)).topologicalClosure