Theorem: MeasureTheory.sigmaFinite_bot_iff
File: Mathlib/MeasureTheory/Measure/Typeclasses.lean

Proof steps:
state_before: α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
inst✝ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s t : Set α
μ : Measure α
⊢ SigmaFinite μ ↔ IsFiniteMeasure μ
state_after: α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
inst✝ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s t : Set α
μ : Measure α
h : SigmaFinite μ
⊢ μ univ < ⊤
tactic: refine
    ⟨fun h => ⟨?_⟩, fun h => by
      haveI := h
      infer_instance⟩
state_before: α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
inst✝ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s t : Set α
μ : Measure α
h : SigmaFinite μ
⊢ μ univ < ⊤
state_after: α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
inst✝ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s t : Set α
μ : Measure α
h this : SigmaFinite μ
⊢ μ univ < ⊤
tactic: haveI : SigmaFinite μ := h
state_before: α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
inst✝ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s t : Set α
μ : Measure α
h this : SigmaFinite μ
⊢ μ univ < ⊤
state_after: α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
inst✝ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s✝ t : Set α
μ : Measure α
h this : SigmaFinite μ
s : ℕ → Set α := spanningSets μ
⊢ μ univ < ⊤
tactic: let s := spanningSets μ
state_before: α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
inst✝ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s✝ t : Set α
μ : Measure α
h this : SigmaFinite μ
s : ℕ → Set α := spanningSets μ
⊢ μ univ < ⊤
state_after: α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
inst✝ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s✝ t : Set α
μ : Measure α
h this : SigmaFinite μ
s : ℕ → Set α := spanningSets μ
hs_univ : ⋃ i, s i = univ
⊢ μ univ < ⊤
tactic: have hs_univ : ⋃ i, s i = Set.univ := iUnion_spanningSets μ
state_before: α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
inst✝ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s✝ t : Set α
μ : Measure α
h this : SigmaFinite μ
s : ℕ → Set α := spanningSets μ
hs_univ : ⋃ i, s i = univ
⊢ μ univ < ⊤
state_after: α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
inst✝ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s✝ t : Set α
μ : Measure α
h this : SigmaFinite μ
s : ℕ → Set α := spanningSets μ
hs_univ : ⋃ i, s i = univ
hs_meas : ∀ (i : ℕ), MeasurableSet (s i)
⊢ μ univ < ⊤
tactic: have hs_meas : ∀ i, MeasurableSet[⊥] (s i) := measurable_spanningSets μ
state_before: α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
inst✝ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s✝ t : Set α
μ : Measure α
h this : SigmaFinite μ
s : ℕ → Set α := spanningSets μ
hs_univ : ⋃ i, s i = univ
hs_meas : ∀ (i : ℕ), MeasurableSet (s i)
⊢ μ univ < ⊤
state_after: α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
inst✝ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s✝ t : Set α
μ : Measure α
h this : SigmaFinite μ
s : ℕ → Set α := spanningSets μ
hs_univ : ⋃ i, s i = univ
hs_meas : ∀ (i : ℕ), s i = ∅ ∨ s i = univ
⊢ μ univ < ⊤
tactic: simp_rw [MeasurableSpace.measurableSet_bot_iff] at hs_meas
state_before: α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
inst✝ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s✝ t : Set α
μ : Measure α
h this : SigmaFinite μ
s : ℕ → Set α := spanningSets μ
hs_univ : ⋃ i, s i = univ
hs_meas : ∀ (i : ℕ), s i = ∅ ∨ s i = univ
⊢ μ univ < ⊤
state_after: case pos
α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
inst✝ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s✝ t : Set α
μ : Measure α
h this : SigmaFinite μ
s : ℕ → Set α := spanningSets μ
hs_univ : ⋃ i, s i = univ
hs_meas : ∀ (i : ℕ), s i = ∅ ∨ s i = univ
h_univ_empty : univ = ∅
⊢ μ univ < ⊤

case neg
α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
inst✝ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s✝ t : Set α
μ : Measure α
h this : SigmaFinite μ
s : ℕ → Set α := spanningSets μ
hs_univ : ⋃ i, s i = univ
hs_meas : ∀ (i : ℕ), s i = ∅ ∨ s i = univ
h_univ_empty : ¬univ = ∅
⊢ μ univ < ⊤
tactic: by_cases h_univ_empty : (Set.univ : Set α) = ∅
state_before: case neg
α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
inst✝ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s✝ t : Set α
μ : Measure α
h this : SigmaFinite μ
s : ℕ → Set α := spanningSets μ
hs_univ : ⋃ i, s i = univ
hs_meas : ∀ (i : ℕ), s i = ∅ ∨ s i = univ
h_univ_empty : ¬univ = ∅
⊢ μ univ < ⊤
state_after: case neg.intro
α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
inst✝ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s✝ t : Set α
μ : Measure α
h this : SigmaFinite μ
s : ℕ → Set α := spanningSets μ
hs_univ : ⋃ i, s i = univ
hs_meas : ∀ (i : ℕ), s i = ∅ ∨ s i = univ
h_univ_empty : ¬univ = ∅
i : ℕ
hsi : s i = univ
⊢ μ univ < ⊤
tactic: obtain ⟨i, hsi⟩ : ∃ i, s i = Set.univ := by
    by_contra! h_not_univ
    have h_empty : ∀ i, s i = ∅ := by simpa [h_not_univ] using hs_meas
    simp only [h_empty, iUnion_empty] at hs_univ
    exact h_univ_empty hs_univ.symm
state_before: case neg.intro
α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
inst✝ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s✝ t : Set α
μ : Measure α
h this : SigmaFinite μ
s : ℕ → Set α := spanningSets μ
hs_univ : ⋃ i, s i = univ
hs_meas : ∀ (i : ℕ), s i = ∅ ∨ s i = univ
h_univ_empty : ¬univ = ∅
i : ℕ
hsi : s i = univ
⊢ μ univ < ⊤
state_after: case neg.intro
α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
inst✝ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s✝ t : Set α
μ : Measure α
h this : SigmaFinite μ
s : ℕ → Set α := spanningSets μ
hs_univ : ⋃ i, s i = univ
hs_meas : ∀ (i : ℕ), s i = ∅ ∨ s i = univ
h_univ_empty : ¬univ = ∅
i : ℕ
hsi : s i = univ
⊢ μ (s i) < ⊤
tactic: rw [← hsi]
state_before: case neg.intro
α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
inst✝ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s✝ t : Set α
μ : Measure α
h this : SigmaFinite μ
s : ℕ → Set α := spanningSets μ
hs_univ : ⋃ i, s i = univ
hs_meas : ∀ (i : ℕ), s i = ∅ ∨ s i = univ
h_univ_empty : ¬univ = ∅
i : ℕ
hsi : s i = univ
⊢ μ (s i) < ⊤
state_after: no goals
tactic: exact measure_spanningSets_lt_top μ i