Theorem: MeasureTheory.Measure.haar.index_union_le
File: Mathlib/MeasureTheory/Measure/Haar/Basic.lean

Proof steps:
state_before: G : Type u_1
inst✝² : Group G
inst✝¹ : TopologicalSpace G
inst✝ : TopologicalGroup G
K₁ K₂ : Compacts G
V : Set G
hV : (interior V).Nonempty
⊢ index (K₁.carrier ∪ K₂.carrier) V ≤ index K₁.carrier V + index K₂.carrier V
state_after: case intro.intro
G : Type u_1
inst✝² : Group G
inst✝¹ : TopologicalSpace G
inst✝ : TopologicalGroup G
K₁ K₂ : Compacts G
V : Set G
hV : (interior V).Nonempty
s : Finset G
h1s : K₁.carrier ⊆ ⋃ g ∈ s, (fun h => g * h) ⁻¹' V
h2s : s.card = index K₁.carrier V
⊢ index (K₁.carrier ∪ K₂.carrier) V ≤ index K₁.carrier V + index K₂.carrier V
tactic: rcases index_elim K₁.2 hV with ⟨s, h1s, h2s⟩
state_before: case intro.intro
G : Type u_1
inst✝² : Group G
inst✝¹ : TopologicalSpace G
inst✝ : TopologicalGroup G
K₁ K₂ : Compacts G
V : Set G
hV : (interior V).Nonempty
s : Finset G
h1s : K₁.carrier ⊆ ⋃ g ∈ s, (fun h => g * h) ⁻¹' V
h2s : s.card = index K₁.carrier V
⊢ index (K₁.carrier ∪ K₂.carrier) V ≤ index K₁.carrier V + index K₂.carrier V
state_after: case intro.intro.intro.intro
G : Type u_1
inst✝² : Group G
inst✝¹ : TopologicalSpace G
inst✝ : TopologicalGroup G
K₁ K₂ : Compacts G
V : Set G
hV : (interior V).Nonempty
s : Finset G
h1s : K₁.carrier ⊆ ⋃ g ∈ s, (fun h => g * h) ⁻¹' V
h2s : s.card = index K₁.carrier V
t : Finset G
h1t : K₂.carrier ⊆ ⋃ g ∈ t, (fun h => g * h) ⁻¹' V
h2t : t.card = index K₂.carrier V
⊢ index (K₁.carrier ∪ K₂.carrier) V ≤ index K₁.carrier V + index K₂.carrier V
tactic: rcases index_elim K₂.2 hV with ⟨t, h1t, h2t⟩
state_before: case intro.intro.intro.intro
G : Type u_1
inst✝² : Group G
inst✝¹ : TopologicalSpace G
inst✝ : TopologicalGroup G
K₁ K₂ : Compacts G
V : Set G
hV : (interior V).Nonempty
s : Finset G
h1s : K₁.carrier ⊆ ⋃ g ∈ s, (fun h => g * h) ⁻¹' V
h2s : s.card = index K₁.carrier V
t : Finset G
h1t : K₂.carrier ⊆ ⋃ g ∈ t, (fun h => g * h) ⁻¹' V
h2t : t.card = index K₂.carrier V
⊢ index (K₁.carrier ∪ K₂.carrier) V ≤ index K₁.carrier V + index K₂.carrier V
state_after: case intro.intro.intro.intro
G : Type u_1
inst✝² : Group G
inst✝¹ : TopologicalSpace G
inst✝ : TopologicalGroup G
K₁ K₂ : Compacts G
V : Set G
hV : (interior V).Nonempty
s : Finset G
h1s : K₁.carrier ⊆ ⋃ g ∈ s, (fun h => g * h) ⁻¹' V
h2s : s.card = index K₁.carrier V
t : Finset G
h1t : K₂.carrier ⊆ ⋃ g ∈ t, (fun h => g * h) ⁻¹' V
h2t : t.card = index K₂.carrier V
⊢ index (K₁.carrier ∪ K₂.carrier) V ≤ s.card + t.card
tactic: rw [← h2s, ← h2t]
state_before: case intro.intro.intro.intro
G : Type u_1
inst✝² : Group G
inst✝¹ : TopologicalSpace G
inst✝ : TopologicalGroup G
K₁ K₂ : Compacts G
V : Set G
hV : (interior V).Nonempty
s : Finset G
h1s : K₁.carrier ⊆ ⋃ g ∈ s, (fun h => g * h) ⁻¹' V
h2s : s.card = index K₁.carrier V
t : Finset G
h1t : K₂.carrier ⊆ ⋃ g ∈ t, (fun h => g * h) ⁻¹' V
h2t : t.card = index K₂.carrier V
⊢ index (K₁.carrier ∪ K₂.carrier) V ≤ s.card + t.card
state_after: case intro.intro.intro.intro
G : Type u_1
inst✝² : Group G
inst✝¹ : TopologicalSpace G
inst✝ : TopologicalGroup G
K₁ K₂ : Compacts G
V : Set G
hV : (interior V).Nonempty
s : Finset G
h1s : K₁.carrier ⊆ ⋃ g ∈ s, (fun h => g * h) ⁻¹' V
h2s : s.card = index K₁.carrier V
t : Finset G
h1t : K₂.carrier ⊆ ⋃ g ∈ t, (fun h => g * h) ⁻¹' V
h2t : t.card = index K₂.carrier V
⊢ index (K₁.carrier ∪ K₂.carrier) V ≤ (s ∪ t).card
tactic: refine le_trans ?_ (Finset.card_union_le _ _)
state_before: case intro.intro.intro.intro
G : Type u_1
inst✝² : Group G
inst✝¹ : TopologicalSpace G
inst✝ : TopologicalGroup G
K₁ K₂ : Compacts G
V : Set G
hV : (interior V).Nonempty
s : Finset G
h1s : K₁.carrier ⊆ ⋃ g ∈ s, (fun h => g * h) ⁻¹' V
h2s : s.card = index K₁.carrier V
t : Finset G
h1t : K₂.carrier ⊆ ⋃ g ∈ t, (fun h => g * h) ⁻¹' V
h2t : t.card = index K₂.carrier V
⊢ index (K₁.carrier ∪ K₂.carrier) V ≤ (s ∪ t).card
state_after: case intro.intro.intro.intro.hm
G : Type u_1
inst✝² : Group G
inst✝¹ : TopologicalSpace G
inst✝ : TopologicalGroup G
K₁ K₂ : Compacts G
V : Set G
hV : (interior V).Nonempty
s : Finset G
h1s : K₁.carrier ⊆ ⋃ g ∈ s, (fun h => g * h) ⁻¹' V
h2s : s.card = index K₁.carrier V
t : Finset G
h1t : K₂.carrier ⊆ ⋃ g ∈ t, (fun h => g * h) ⁻¹' V
h2t : t.card = index K₂.carrier V
⊢ (s ∪ t).card ∈ Finset.card '' {t | K₁.carrier ∪ K₂.carrier ⊆ ⋃ g ∈ t, (fun h => g * h) ⁻¹' V}
tactic: apply Nat.sInf_le
state_before: case intro.intro.intro.intro.hm
G : Type u_1
inst✝² : Group G
inst✝¹ : TopologicalSpace G
inst✝ : TopologicalGroup G
K₁ K₂ : Compacts G
V : Set G
hV : (interior V).Nonempty
s : Finset G
h1s : K₁.carrier ⊆ ⋃ g ∈ s, (fun h => g * h) ⁻¹' V
h2s : s.card = index K₁.carrier V
t : Finset G
h1t : K₂.carrier ⊆ ⋃ g ∈ t, (fun h => g * h) ⁻¹' V
h2t : t.card = index K₂.carrier V
⊢ (s ∪ t).card ∈ Finset.card '' {t | K₁.carrier ∪ K₂.carrier ⊆ ⋃ g ∈ t, (fun h => g * h) ⁻¹' V}
state_after: case intro.intro.intro.intro.hm
G : Type u_1
inst✝² : Group G
inst✝¹ : TopologicalSpace G
inst✝ : TopologicalGroup G
K₁ K₂ : Compacts G
V : Set G
hV : (interior V).Nonempty
s : Finset G
h1s : K₁.carrier ⊆ ⋃ g ∈ s, (fun h => g * h) ⁻¹' V
h2s : s.card = index K₁.carrier V
t : Finset G
h1t : K₂.carrier ⊆ ⋃ g ∈ t, (fun h => g * h) ⁻¹' V
h2t : t.card = index K₂.carrier V
⊢ s ∪ t ∈ {t | K₁.carrier ∪ K₂.carrier ⊆ ⋃ g ∈ t, (fun h => g * h) ⁻¹' V}
tactic: refine ⟨_, ?_, rfl⟩
state_before: case intro.intro.intro.intro.hm
G : Type u_1
inst✝² : Group G
inst✝¹ : TopologicalSpace G
inst✝ : TopologicalGroup G
K₁ K₂ : Compacts G
V : Set G
hV : (interior V).Nonempty
s : Finset G
h1s : K₁.carrier ⊆ ⋃ g ∈ s, (fun h => g * h) ⁻¹' V
h2s : s.card = index K₁.carrier V
t : Finset G
h1t : K₂.carrier ⊆ ⋃ g ∈ t, (fun h => g * h) ⁻¹' V
h2t : t.card = index K₂.carrier V
⊢ s ∪ t ∈ {t | K₁.carrier ∪ K₂.carrier ⊆ ⋃ g ∈ t, (fun h => g * h) ⁻¹' V}
state_after: case intro.intro.intro.intro.hm
G : Type u_1
inst✝² : Group G
inst✝¹ : TopologicalSpace G
inst✝ : TopologicalGroup G
K₁ K₂ : Compacts G
V : Set G
hV : (interior V).Nonempty
s : Finset G
h1s : K₁.carrier ⊆ ⋃ g ∈ s, (fun h => g * h) ⁻¹' V
h2s : s.card = index K₁.carrier V
t : Finset G
h1t : K₂.carrier ⊆ ⋃ g ∈ t, (fun h => g * h) ⁻¹' V
h2t : t.card = index K₂.carrier V
⊢ K₁.carrier ∪ K₂.carrier ⊆ ⋃ g ∈ s ∪ t, (fun h => g * h) ⁻¹' V
tactic: rw [mem_setOf_eq]
state_before: case intro.intro.intro.intro.hm
G : Type u_1
inst✝² : Group G
inst✝¹ : TopologicalSpace G
inst✝ : TopologicalGroup G
K₁ K₂ : Compacts G
V : Set G
hV : (interior V).Nonempty
s : Finset G
h1s : K₁.carrier ⊆ ⋃ g ∈ s, (fun h => g * h) ⁻¹' V
h2s : s.card = index K₁.carrier V
t : Finset G
h1t : K₂.carrier ⊆ ⋃ g ∈ t, (fun h => g * h) ⁻¹' V
h2t : t.card = index K₂.carrier V
⊢ K₁.carrier ∪ K₂.carrier ⊆ ⋃ g ∈ s ∪ t, (fun h => g * h) ⁻¹' V
state_after: no goals
tactic: apply union_subset <;> refine Subset.trans (by assumption) ?_ <;>
    apply biUnion_subset_biUnion_left <;> intro g hg <;> simp only [mem_def] at hg <;>
    simp only [mem_def, Multiset.mem_union, Finset.union_val, hg, or_true_iff, true_or_iff]