-- Mathlib/MeasureTheory/Integral/RieszMarkovKakutani/Basic.lean
lemma contentRegular_rieszContent : (rieszContent Λ).ContentRegular

Proof state:
X : Type u_1
inst✝² : TopologicalSpace X
Λ : (X →C_c ℝ≥0) →ₗ[ℝ≥0] ℝ≥0
inst✝¹ : T2Space X
inst✝ : LocallyCompactSpace X
K : Compacts X
⊢ ∀ (b : ℝ≥0∞), (∀ (i : Compacts X), b ≤ ⨅ (_ : ↑K ⊆ interior ↑i), ↑(rieszContentAux Λ i)) → b ≤ ↑(rieszContentAux Λ K)

Tactic:
intro b hb

Result:
X : Type u_1
inst✝² : TopologicalSpace X
Λ : (X →C_c ℝ≥0) →ₗ[ℝ≥0] ℝ≥0
inst✝¹ : T2Space X
inst✝ : LocallyCompactSpace X
K : Compacts X
b : ℝ≥0∞
hb : ∀ (i : Compacts X), b ≤ ⨅ (_ : ↑K ⊆ interior ↑i), ↑(rieszContentAux Λ i)
⊢ b ≤ ↑(rieszContentAux Λ K)

Proof state:
X : Type u_1
inst✝² : TopologicalSpace X
Λ : (X →C_c ℝ≥0) →ₗ[ℝ≥0] ℝ≥0
inst✝¹ : T2Space X
inst✝ : LocallyCompactSpace X
K : Compacts X
b : ℝ≥0∞
hb : ∀ (i : Compacts X), b ≤ ⨅ (_ : ↑K ⊆ interior ↑i), ↑(rieszContentAux Λ i)
this : b < ⊤
⊢ ↑b.toNNReal ≤ ↑(sInf (⇑Λ '' {f | ∀ x ∈ K, 1 ≤ f x}))

Tactic:
apply le_iff_forall_pos_le_add.mpr

Result:
X : Type u_1
inst✝² : TopologicalSpace X
Λ : (X →C_c ℝ≥0) →ₗ[ℝ≥0] ℝ≥0
inst✝¹ : T2Space X
inst✝ : LocallyCompactSpace X
K : Compacts X
b : ℝ≥0∞
hb : ∀ (i : Compacts X), b ≤ ⨅ (_ : ↑K ⊆ interior ↑i), ↑(rieszContentAux Λ i)
this : b < ⊤
⊢ ∀ (ε : ℝ), 0 < ε → ↑b.toNNReal ≤ ↑(sInf (⇑Λ '' {f | ∀ x ∈ K, 1 ≤ f x})) + ε

Proof state:
X : Type u_1
inst✝² : TopologicalSpace X
Λ : (X →C_c ℝ≥0) →ₗ[ℝ≥0] ℝ≥0
inst✝¹ : T2Space X
inst✝ : LocallyCompactSpace X
K : Compacts X
b : ℝ≥0∞
hb : ∀ (i : Compacts X), b ≤ ⨅ (_ : ↑K ⊆ interior ↑i), ↑(rieszContentAux Λ i)
⊢ ∃ p, b = ↑p ∧ p ≤ sInf (⇑Λ '' {f | ∀ x ∈ K, 1 ≤ f x})

Tactic:
have : b < ⊤ := by
  obtain ⟨F, hF⟩ := exists_compact_superset K.2
  exact (le_iInf_iff.mp (hb ⟨F, hF.1⟩) hF.2).trans_lt ENNReal.coe_lt_top

Result:
X : Type u_1
inst✝² : TopologicalSpace X
Λ : (X →C_c ℝ≥0) →ₗ[ℝ≥0] ℝ≥0
inst✝¹ : T2Space X
inst✝ : LocallyCompactSpace X
K : Compacts X
b : ℝ≥0∞
hb : ∀ (i : Compacts X), b ≤ ⨅ (_ : ↑K ⊆ interior ↑i), ↑(rieszContentAux Λ i)
this : b < ⊤
⊢ ∃ p, b = ↑p ∧ p ≤ sInf (⇑Λ '' {f | ∀ x ∈ K, 1 ≤ f x})

Proof state:
X : Type u_1
inst✝² : TopologicalSpace X
Λ : (X →C_c ℝ≥0) →ₗ[ℝ≥0] ℝ≥0
inst✝¹ : T2Space X
inst✝ : LocallyCompactSpace X
K : Compacts X
⊢ (∀ (i : Compacts X), ↑K ⊆ interior ↑i → rieszContentAux Λ K ≤ rieszContentAux Λ i) ∧
    ⨅ K', ⨅ (_ : ↑K ⊆ interior ↑K'), ↑(rieszContentAux Λ K') ≤ ↑(rieszContentAux Λ K)

Tactic:
refine ⟨fun K' hK' ↦ rieszContentAux_mono Λ (hK'.trans interior_subset), ?_⟩

Result:
X : Type u_1
inst✝² : TopologicalSpace X
Λ : (X →C_c ℝ≥0) →ₗ[ℝ≥0] ℝ≥0
inst✝¹ : T2Space X
inst✝ : LocallyCompactSpace X
K : Compacts X
⊢ ⨅ K', ⨅ (_ : ↑K ⊆ interior ↑K'), ↑(rieszContentAux Λ K') ≤ ↑(rieszContentAux Λ K)

Proof state:
case intro.intro.intro
X : Type u_1
inst✝² : TopologicalSpace X
Λ : (X →C_c ℝ≥0) →ₗ[ℝ≥0] ℝ≥0
inst✝¹ : T2Space X
inst✝ : LocallyCompactSpace X
K : Compacts X
b : ℝ≥0∞
hb : ∀ (i : Compacts X), b ≤ ⨅ (_ : ↑K ⊆ interior ↑i), ↑(rieszContentAux Λ i)
this : b < ⊤
ε : ℝ≥0
hε : 0 < ↑ε
f : X →C_c ℝ≥0
hfleoneonK : ∀ x ∈ K, 1 ≤ f x
hfle : ↑(Λ f) < ↑(sInf (⇑Λ '' {f | ∀ x ∈ K, 1 ≤ f x}) + ⟨↑ε, ⋯⟩)
α : ℝ≥0
hα : 1 < α
K' : Set X := ⇑f ⁻¹' Ici α⁻¹
hKK' : ↑K ⊆ interior K'
⊢ b.toNNReal ≤ Λ (α • f)

Tactic:
have hK'cp : IsCompact K' := .of_isClosed_subset f.2 (isClosed_Ici.preimage f.1.2) fun x hx ↦
  subset_closure ((inv_pos_of_pos <| zero_lt_one.trans hα).trans_le hx).ne'

Result:
case intro.intro.intro
X : Type u_1
inst✝² : TopologicalSpace X
Λ : (X →C_c ℝ≥0) →ₗ[ℝ≥0] ℝ≥0
inst✝¹ : T2Space X
inst✝ : LocallyCompactSpace X
K : Compacts X
b : ℝ≥0∞
hb : ∀ (i : Compacts X), b ≤ ⨅ (_ : ↑K ⊆ interior ↑i), ↑(rieszContentAux Λ i)
this : b < ⊤
ε : ℝ≥0
hε : 0 < ↑ε
f : X →C_c ℝ≥0
hfleoneonK : ∀ x ∈ K, 1 ≤ f x
hfle : ↑(Λ f) < ↑(sInf (⇑Λ '' {f | ∀ x ∈ K, 1 ≤ f x}) + ⟨↑ε, ⋯⟩)
α : ℝ≥0
hα : 1 < α
K' : Set X := ⇑f ⁻¹' Ici α⁻¹
hKK' : ↑K ⊆ interior K'
hK'cp : IsCompact K'
⊢ b.toNNReal ≤ Λ (α • f)

Proof state:
X : Type u_1
inst✝² : TopologicalSpace X
Λ : (X →C_c ℝ≥0) →ₗ[ℝ≥0] ℝ≥0
inst✝¹ : T2Space X
inst✝ : LocallyCompactSpace X
K : Compacts X
b : ℝ≥0∞
hb : ∀ (i : Compacts X), b ≤ ⨅ (_ : ↑K ⊆ interior ↑i), ↑(rieszContentAux Λ i)
this : b < ⊤
⊢ ∀ (ε : ℝ), 0 < ε → ↑b.toNNReal ≤ ↑(sInf (⇑Λ '' {f | ∀ x ∈ K, 1 ≤ f x})) + ε

Tactic:
intro ε hε

Result:
X : Type u_1
inst✝² : TopologicalSpace X
Λ : (X →C_c ℝ≥0) →ₗ[ℝ≥0] ℝ≥0
inst✝¹ : T2Space X
inst✝ : LocallyCompactSpace X
K : Compacts X
b : ℝ≥0∞
hb : ∀ (i : Compacts X), b ≤ ⨅ (_ : ↑K ⊆ interior ↑i), ↑(rieszContentAux Λ i)
this : b < ⊤
ε : ℝ
hε : 0 < ε
⊢ ↑b.toNNReal ≤ ↑(sInf (⇑Λ '' {f | ∀ x ∈ K, 1 ≤ f x})) + ε

Proof state:
case intro.intro.intro
X : Type u_1
inst✝² : TopologicalSpace X
Λ : (X →C_c ℝ≥0) →ₗ[ℝ≥0] ℝ≥0
inst✝¹ : T2Space X
inst✝ : LocallyCompactSpace X
K : Compacts X
b : ℝ≥0∞
hb : ∀ (i : Compacts X), b ≤ ⨅ (_ : ↑K ⊆ interior ↑i), ↑(rieszContentAux Λ i)
this : b < ⊤
ε : ℝ≥0
hε : 0 < ↑ε
f : X →C_c ℝ≥0
hfleoneonK : ∀ x ∈ K, 1 ≤ f x
hfle : ↑(Λ f) < ↑(sInf (⇑Λ '' {f | ∀ x ∈ K, 1 ≤ f x}) + ⟨↑ε, ⋯⟩)
α : ℝ≥0
hα : 1 < α
⊢ b.toNNReal ≤ Λ (α • f)

Tactic:
set K' := f ⁻¹' Ici α⁻¹

Result:
case intro.intro.intro
X : Type u_1
inst✝² : TopologicalSpace X
Λ : (X →C_c ℝ≥0) →ₗ[ℝ≥0] ℝ≥0
inst✝¹ : T2Space X
inst✝ : LocallyCompactSpace X
K : Compacts X
b : ℝ≥0∞
hb : ∀ (i : Compacts X), b ≤ ⨅ (_ : ↑K ⊆ interior ↑i), ↑(rieszContentAux Λ i)
this : b < ⊤
ε : ℝ≥0
hε : 0 < ↑ε
f : X →C_c ℝ≥0
hfleoneonK : ∀ x ∈ K, 1 ≤ f x
hfle : ↑(Λ f) < ↑(sInf (⇑Λ '' {f | ∀ x ∈ K, 1 ≤ f x}) + ⟨↑ε, ⋯⟩)
α : ℝ≥0
hα : 1 < α
K' : Set X := ⇑f ⁻¹' Ici α⁻¹
⊢ b.toNNReal ≤ Λ (α • f)

Proof state:
X : Type u_1
inst✝² : TopologicalSpace X
Λ : (X →C_c ℝ≥0) →ₗ[ℝ≥0] ℝ≥0
inst✝¹ : T2Space X
inst✝ : LocallyCompactSpace X
K : Compacts X
b : ℝ≥0∞
hb : ∀ (i : Compacts X), b ≤ ⨅ (_ : ↑K ⊆ interior ↑i), ↑(rieszContentAux Λ i)
this : b < ⊤
ε : ℝ≥0
hε : 0 < ↑ε
f : X →C_c ℝ≥0
hfleoneonK : ∀ x ∈ K, 1 ≤ f x
hfle : ↑(Λ f) < ↑(sInf (⇑Λ '' {f | ∀ x ∈ K, 1 ≤ f x}) + ⟨↑ε, ⋯⟩)
α : ℝ≥0
hα : 1 < α
K' : Set X := ⇑f ⁻¹' Ici α⁻¹
hKK' : ↑K ⊆ interior K'
hK'cp : IsCompact K'
hb' : ↑K ⊆ interior K' → b ≤ ↑(rieszContentAux Λ { carrier := K', isCompact' := hK'cp })
⊢ ↑(rieszContentAux Λ { carrier := K', isCompact' := hK'cp }) ≠ ⊤

Tactic:
simp

Result:
no goals

Proof state:
X : Type u_1
inst✝² : TopologicalSpace X
Λ : (X →C_c ℝ≥0) →ₗ[ℝ≥0] ℝ≥0
inst✝¹ : T2Space X
inst✝ : LocallyCompactSpace X
K : Compacts X
b : ℝ≥0∞
hb : ∀ (i : Compacts X), b ≤ ⨅ (_ : ↑K ⊆ interior ↑i), ↑(rieszContentAux Λ i)
this : b < ⊤
⊢ ∃ p, b = ↑p ∧ p ≤ sInf (⇑Λ '' {f | ∀ x ∈ K, 1 ≤ f x})

Tactic:
refine ⟨b.toNNReal, (ENNReal.coe_toNNReal this.ne).symm, NNReal.coe_le_coe.mp ?_⟩

Result:
X : Type u_1
inst✝² : TopologicalSpace X
Λ : (X →C_c ℝ≥0) →ₗ[ℝ≥0] ℝ≥0
inst✝¹ : T2Space X
inst✝ : LocallyCompactSpace X
K : Compacts X
b : ℝ≥0∞
hb : ∀ (i : Compacts X), b ≤ ⨅ (_ : ↑K ⊆ interior ↑i), ↑(rieszContentAux Λ i)
this : b < ⊤
⊢ ↑b.toNNReal ≤ ↑(sInf (⇑Λ '' {f | ∀ x ∈ K, 1 ≤ f x}))

Proof state:
X : Type u_1
inst✝² : TopologicalSpace X
Λ : (X →C_c ℝ≥0) →ₗ[ℝ≥0] ℝ≥0
inst✝¹ : T2Space X
inst✝ : LocallyCompactSpace X
K : Compacts X
b : ℝ≥0∞
hb : ∀ (i : Compacts X), b ≤ ⨅ (_ : ↑K ⊆ interior ↑i), ↑(rieszContentAux Λ i)
⊢ b < ⊤

Tactic:
obtain ⟨F, hF⟩ := exists_compact_superset K.2

Result:
case intro
X : Type u_1
inst✝² : TopologicalSpace X
Λ : (X →C_c ℝ≥0) →ₗ[ℝ≥0] ℝ≥0
inst✝¹ : T2Space X
inst✝ : LocallyCompactSpace X
K : Compacts X
b : ℝ≥0∞
hb : ∀ (i : Compacts X), b ≤ ⨅ (_ : ↑K ⊆ interior ↑i), ↑(rieszContentAux Λ i)
F : Set X
hF : IsCompact F ∧ K.carrier ⊆ interior F
⊢ b < ⊤