Theorem: PartitionOfUnity.finite_tsupport
File: Mathlib/Topology/PartitionOfUnity.lean

Proof steps:
state_before: ι : Type u
X : Type v
inst✝⁴ : TopologicalSpace X
E : Type u_1
inst✝³ : AddCommMonoid E
inst✝² : SMulWithZero ℝ E
inst✝¹ : TopologicalSpace E
inst✝ : ContinuousSMul ℝ E
s✝ : Set X
f : PartitionOfUnity ι X s✝
s : Set X
ρ : PartitionOfUnity ι X s
x₀ : X
⊢ {i | x₀ ∈ tsupport ⇑(ρ i)}.Finite
state_after: case intro.intro
ι : Type u
X : Type v
inst✝⁴ : TopologicalSpace X
E : Type u_1
inst✝³ : AddCommMonoid E
inst✝² : SMulWithZero ℝ E
inst✝¹ : TopologicalSpace E
inst✝ : ContinuousSMul ℝ E
s✝ : Set X
f : PartitionOfUnity ι X s✝
s : Set X
ρ : PartitionOfUnity ι X s
x₀ : X
t : Set X
t_in : t ∈ 𝓝 x₀
ht : {i | ((fun i => support ⇑(ρ i)) i ∩ t).Nonempty}.Finite
⊢ {i | x₀ ∈ tsupport ⇑(ρ i)}.Finite
tactic: rcases ρ.locallyFinite x₀ with ⟨t, t_in, ht⟩
state_before: case intro.intro
ι : Type u
X : Type v
inst✝⁴ : TopologicalSpace X
E : Type u_1
inst✝³ : AddCommMonoid E
inst✝² : SMulWithZero ℝ E
inst✝¹ : TopologicalSpace E
inst✝ : ContinuousSMul ℝ E
s✝ : Set X
f : PartitionOfUnity ι X s✝
s : Set X
ρ : PartitionOfUnity ι X s
x₀ : X
t : Set X
t_in : t ∈ 𝓝 x₀
ht : {i | ((fun i => support ⇑(ρ i)) i ∩ t).Nonempty}.Finite
⊢ {i | x₀ ∈ tsupport ⇑(ρ i)}.Finite
state_after: case intro.intro
ι : Type u
X : Type v
inst✝⁴ : TopologicalSpace X
E : Type u_1
inst✝³ : AddCommMonoid E
inst✝² : SMulWithZero ℝ E
inst✝¹ : TopologicalSpace E
inst✝ : ContinuousSMul ℝ E
s✝ : Set X
f : PartitionOfUnity ι X s✝
s : Set X
ρ : PartitionOfUnity ι X s
x₀ : X
t : Set X
t_in : t ∈ 𝓝 x₀
ht : {i | ((fun i => support ⇑(ρ i)) i ∩ t).Nonempty}.Finite
⊢ {i | x₀ ∈ tsupport ⇑(ρ i)} ⊆ {i | ((fun i => support ⇑(ρ i)) i ∩ t).Nonempty}
tactic: apply ht.subset
state_before: case intro.intro
ι : Type u
X : Type v
inst✝⁴ : TopologicalSpace X
E : Type u_1
inst✝³ : AddCommMonoid E
inst✝² : SMulWithZero ℝ E
inst✝¹ : TopologicalSpace E
inst✝ : ContinuousSMul ℝ E
s✝ : Set X
f : PartitionOfUnity ι X s✝
s : Set X
ρ : PartitionOfUnity ι X s
x₀ : X
t : Set X
t_in : t ∈ 𝓝 x₀
ht : {i | ((fun i => support ⇑(ρ i)) i ∩ t).Nonempty}.Finite
⊢ {i | x₀ ∈ tsupport ⇑(ρ i)} ⊆ {i | ((fun i => support ⇑(ρ i)) i ∩ t).Nonempty}
state_after: case intro.intro
ι : Type u
X : Type v
inst✝⁴ : TopologicalSpace X
E : Type u_1
inst✝³ : AddCommMonoid E
inst✝² : SMulWithZero ℝ E
inst✝¹ : TopologicalSpace E
inst✝ : ContinuousSMul ℝ E
s✝ : Set X
f : PartitionOfUnity ι X s✝
s : Set X
ρ : PartitionOfUnity ι X s
x₀ : X
t : Set X
t_in : t ∈ 𝓝 x₀
ht : {i | ((fun i => support ⇑(ρ i)) i ∩ t).Nonempty}.Finite
i : ι
hi : i ∈ {i | x₀ ∈ tsupport ⇑(ρ i)}
⊢ i ∈ {i | ((fun i => support ⇑(ρ i)) i ∩ t).Nonempty}
tactic: rintro i hi
state_before: case intro.intro
ι : Type u
X : Type v
inst✝⁴ : TopologicalSpace X
E : Type u_1
inst✝³ : AddCommMonoid E
inst✝² : SMulWithZero ℝ E
inst✝¹ : TopologicalSpace E
inst✝ : ContinuousSMul ℝ E
s✝ : Set X
f : PartitionOfUnity ι X s✝
s : Set X
ρ : PartitionOfUnity ι X s
x₀ : X
t : Set X
t_in : t ∈ 𝓝 x₀
ht : {i | ((fun i => support ⇑(ρ i)) i ∩ t).Nonempty}.Finite
i : ι
hi : i ∈ {i | x₀ ∈ tsupport ⇑(ρ i)}
⊢ i ∈ {i | ((fun i => support ⇑(ρ i)) i ∩ t).Nonempty}
state_after: case intro.intro
ι : Type u
X : Type v
inst✝⁴ : TopologicalSpace X
E : Type u_1
inst✝³ : AddCommMonoid E
inst✝² : SMulWithZero ℝ E
inst✝¹ : TopologicalSpace E
inst✝ : ContinuousSMul ℝ E
s✝ : Set X
f : PartitionOfUnity ι X s✝
s : Set X
ρ : PartitionOfUnity ι X s
x₀ : X
t : Set X
t_in : t ∈ 𝓝 x₀
ht : {i | ((fun i => support ⇑(ρ i)) i ∩ t).Nonempty}.Finite
i : ι
hi : i ∈ {i | x₀ ∈ tsupport ⇑(ρ i)}
⊢ i ∈ {i | (t ∩ support ⇑(ρ i)).Nonempty}
tactic: simp only [inter_comm]
state_before: case intro.intro
ι : Type u
X : Type v
inst✝⁴ : TopologicalSpace X
E : Type u_1
inst✝³ : AddCommMonoid E
inst✝² : SMulWithZero ℝ E
inst✝¹ : TopologicalSpace E
inst✝ : ContinuousSMul ℝ E
s✝ : Set X
f : PartitionOfUnity ι X s✝
s : Set X
ρ : PartitionOfUnity ι X s
x₀ : X
t : Set X
t_in : t ∈ 𝓝 x₀
ht : {i | ((fun i => support ⇑(ρ i)) i ∩ t).Nonempty}.Finite
i : ι
hi : i ∈ {i | x₀ ∈ tsupport ⇑(ρ i)}
⊢ i ∈ {i | (t ∩ support ⇑(ρ i)).Nonempty}
state_after: no goals
tactic: exact mem_closure_iff_nhds.mp hi t t_in