Theorem: PartitionOfUnity.sum_finsupport'
File: Mathlib/Topology/PartitionOfUnity.lean

tactic: classical
rw [← Finset.sum_sdiff hI, ρ.sum_finsupport hx₀]
suffices ∑ i ∈ I \ ρ.finsupport x₀, (ρ i) x₀ = ∑ i ∈ I \ ρ.finsupport x₀, 0 by
  rw [this, add_left_eq_self, Finset.sum_const_zero]
apply Finset.sum_congr rfl
rintro x hx
simp only [Finset.mem_sdiff, ρ.mem_finsupport, mem_support, Classical.not_not] at hx
exact hx.2
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✝ x₀ : X
hx₀ : x₀ ∈ s
I : Finset ι
hI : ρ.finsupport x₀ ⊆ I
⊢ ∑ i ∈ I, (ρ i) x₀ = 1
state_after: no goals

tactic: rw [← Finset.sum_sdiff hI, ρ.sum_finsupport hx₀]
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✝ x₀ : X
hx₀ : x₀ ∈ s
I : Finset ι
hI : ρ.finsupport x₀ ⊆ I
⊢ ∑ i ∈ I, (ρ i) x₀ = 1
state_after: 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✝ x₀ : X
hx₀ : x₀ ∈ s
I : Finset ι
hI : ρ.finsupport x₀ ⊆ I
⊢ ∑ x ∈ I \ ρ.finsupport x₀, (ρ x) x₀ + 1 = 1

tactic: suffices ∑ i ∈ I \ ρ.finsupport x₀, (ρ i) x₀ = ∑ i ∈ I \ ρ.finsupport x₀, 0 by
  rw [this, add_left_eq_self, Finset.sum_const_zero]
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✝ x₀ : X
hx₀ : x₀ ∈ s
I : Finset ι
hI : ρ.finsupport x₀ ⊆ I
⊢ ∑ x ∈ I \ ρ.finsupport x₀, (ρ x) x₀ + 1 = 1
state_after: 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✝ x₀ : X
hx₀ : x₀ ∈ s
I : Finset ι
hI : ρ.finsupport x₀ ⊆ I
⊢ ∑ i ∈ I \ ρ.finsupport x₀, (ρ i) x₀ = ∑ i ∈ I \ ρ.finsupport x₀, 0

tactic: apply Finset.sum_congr rfl
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✝ x₀ : X
hx₀ : x₀ ∈ s
I : Finset ι
hI : ρ.finsupport x₀ ⊆ I
⊢ ∑ i ∈ I \ ρ.finsupport x₀, (ρ i) x₀ = ∑ i ∈ I \ ρ.finsupport x₀, 0
state_after: 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✝ x₀ : X
hx₀ : x₀ ∈ s
I : Finset ι
hI : ρ.finsupport x₀ ⊆ I
⊢ ∀ x ∈ I \ ρ.finsupport x₀, (ρ x) x₀ = 0

tactic: rintro x hx
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✝ x₀ : X
hx₀ : x₀ ∈ s
I : Finset ι
hI : ρ.finsupport x₀ ⊆ I
⊢ ∀ x ∈ I \ ρ.finsupport x₀, (ρ x) x₀ = 0
state_after: 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✝ x₀ : X
hx₀ : x₀ ∈ s
I : Finset ι
hI : ρ.finsupport x₀ ⊆ I
x : ι
hx : x ∈ I \ ρ.finsupport x₀
⊢ (ρ x) x₀ = 0

tactic: simp only [Finset.mem_sdiff, ρ.mem_finsupport, mem_support, Classical.not_not] at hx
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✝ x₀ : X
hx₀ : x₀ ∈ s
I : Finset ι
hI : ρ.finsupport x₀ ⊆ I
x : ι
hx : x ∈ I \ ρ.finsupport x₀
⊢ (ρ x) x₀ = 0
state_after: 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✝ x₀ : X
hx₀ : x₀ ∈ s
I : Finset ι
hI : ρ.finsupport x₀ ⊆ I
x : ι
hx : x ∈ I ∧ (ρ x) x₀ = 0
⊢ (ρ x) x₀ = 0

tactic: exact hx.2
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✝ x₀ : X
hx₀ : x₀ ∈ s
I : Finset ι
hI : ρ.finsupport x₀ ⊆ I
x : ι
hx : x ∈ I ∧ (ρ x) x₀ = 0
⊢ (ρ x) x₀ = 0
state_after: no goals

tactic: rw [this, add_left_eq_self, Finset.sum_const_zero]
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✝ x₀ : X
hx₀ : x₀ ∈ s
I : Finset ι
hI : ρ.finsupport x₀ ⊆ I
this : ∑ i ∈ I \ ρ.finsupport x₀, (ρ i) x₀ = ∑ i ∈ I \ ρ.finsupport x₀, 0
⊢ ∑ x ∈ I \ ρ.finsupport x₀, (ρ x) x₀ + 1 = 1
state_after: no goals