Theorem: unique_topology_of_t2
File: Mathlib/Topology/Algebra/Module/FiniteDimension.lean

tactic: refine' TopologicalAddGroup.ext h₁ inferInstance (le_antisymm _ _)
state_before: 𝕜 : Type u
hnorm : NontriviallyNormedField 𝕜
E : Type v
inst✝¹⁴ : AddCommGroup E
inst✝¹³ : Module 𝕜 E
inst✝¹² : TopologicalSpace E
inst✝¹¹ : TopologicalAddGroup E
inst✝¹⁰ : ContinuousSMul 𝕜 E
F : Type w
inst✝⁹ : AddCommGroup F
inst✝⁸ : Module 𝕜 F
inst✝⁷ : TopologicalSpace F
inst✝⁶ : TopologicalAddGroup F
inst✝⁵ : ContinuousSMul 𝕜 F
F' : Type x
inst✝⁴ : AddCommGroup F'
inst✝³ : Module 𝕜 F'
inst✝² : TopologicalSpace F'
inst✝¹ : TopologicalAddGroup F'
inst✝ : ContinuousSMul 𝕜 F'
t : TopologicalSpace 𝕜
h₁ : TopologicalAddGroup 𝕜
h₂ : ContinuousSMul 𝕜 𝕜
h₃ : T2Space 𝕜
⊢ t = UniformSpace.toTopologicalSpace

tactic: rw [Metric.nhds_basis_closedBall.ge_iff]
state_before: case refine'_1
𝕜 : Type u
hnorm : NontriviallyNormedField 𝕜
E : Type v
inst✝¹⁴ : AddCommGroup E
inst✝¹³ : Module 𝕜 E
inst✝¹² : TopologicalSpace E
inst✝¹¹ : TopologicalAddGroup E
inst✝¹⁰ : ContinuousSMul 𝕜 E
F : Type w
inst✝⁹ : AddCommGroup F
inst✝⁸ : Module 𝕜 F
inst✝⁷ : TopologicalSpace F
inst✝⁶ : TopologicalAddGroup F
inst✝⁵ : ContinuousSMul 𝕜 F
F' : Type x
inst✝⁴ : AddCommGroup F'
inst✝³ : Module 𝕜 F'
inst✝² : TopologicalSpace F'
inst✝¹ : TopologicalAddGroup F'
inst✝ : ContinuousSMul 𝕜 F'
t : TopologicalSpace 𝕜
h₁ : TopologicalAddGroup 𝕜
h₂ : ContinuousSMul 𝕜 𝕜
h₃ : T2Space 𝕜
⊢ nhds 0 ≤ nhds 0

tactic: intro ε hε
state_before: case refine'_1
𝕜 : Type u
hnorm : NontriviallyNormedField 𝕜
E : Type v
inst✝¹⁴ : AddCommGroup E
inst✝¹³ : Module 𝕜 E
inst✝¹² : TopologicalSpace E
inst✝¹¹ : TopologicalAddGroup E
inst✝¹⁰ : ContinuousSMul 𝕜 E
F : Type w
inst✝⁹ : AddCommGroup F
inst✝⁸ : Module 𝕜 F
inst✝⁷ : TopologicalSpace F
inst✝⁶ : TopologicalAddGroup F
inst✝⁵ : ContinuousSMul 𝕜 F
F' : Type x
inst✝⁴ : AddCommGroup F'
inst✝³ : Module 𝕜 F'
inst✝² : TopologicalSpace F'
inst✝¹ : TopologicalAddGroup F'
inst✝ : ContinuousSMul 𝕜 F'
t : TopologicalSpace 𝕜
h₁ : TopologicalAddGroup 𝕜
h₂ : ContinuousSMul 𝕜 𝕜
h₃ : T2Space 𝕜
⊢ ∀ (i' : ℝ), 0 < i' → Metric.closedBall 0 i' ∈ nhds 0

tactic: rcases NormedField.exists_norm_lt 𝕜 hε with ⟨ξ₀, hξ₀, hξ₀ε⟩
state_before: case refine'_1
𝕜 : Type u
hnorm : NontriviallyNormedField 𝕜
E : Type v
inst✝¹⁴ : AddCommGroup E
inst✝¹³ : Module 𝕜 E
inst✝¹² : TopologicalSpace E
inst✝¹¹ : TopologicalAddGroup E
inst✝¹⁰ : ContinuousSMul 𝕜 E
F : Type w
inst✝⁹ : AddCommGroup F
inst✝⁸ : Module 𝕜 F
inst✝⁷ : TopologicalSpace F
inst✝⁶ : TopologicalAddGroup F
inst✝⁵ : ContinuousSMul 𝕜 F
F' : Type x
inst✝⁴ : AddCommGroup F'
inst✝³ : Module 𝕜 F'
inst✝² : TopologicalSpace F'
inst✝¹ : TopologicalAddGroup F'
inst✝ : ContinuousSMul 𝕜 F'
t : TopologicalSpace 𝕜
h₁ : TopologicalAddGroup 𝕜
h₂ : ContinuousSMul 𝕜 𝕜
h₃ : T2Space 𝕜
ε : ℝ
hε : 0 < ε
⊢ Metric.closedBall 0 ε ∈ nhds 0

tactic: have : {ξ₀}ᶜ ∈ @nhds 𝕜 t 0 := IsOpen.mem_nhds isOpen_compl_singleton <|
  mem_compl_singleton_iff.mpr <| Ne.symm <| norm_ne_zero_iff.mp hξ₀.ne.symm
state_before: case refine'_1.intro.intro
𝕜 : Type u
hnorm : NontriviallyNormedField 𝕜
E : Type v
inst✝¹⁴ : AddCommGroup E
inst✝¹³ : Module 𝕜 E
inst✝¹² : TopologicalSpace E
inst✝¹¹ : TopologicalAddGroup E
inst✝¹⁰ : ContinuousSMul 𝕜 E
F : Type w
inst✝⁹ : AddCommGroup F
inst✝⁸ : Module 𝕜 F
inst✝⁷ : TopologicalSpace F
inst✝⁶ : TopologicalAddGroup F
inst✝⁵ : ContinuousSMul 𝕜 F
F' : Type x
inst✝⁴ : AddCommGroup F'
inst✝³ : Module 𝕜 F'
inst✝² : TopologicalSpace F'
inst✝¹ : TopologicalAddGroup F'
inst✝ : ContinuousSMul 𝕜 F'
t : TopologicalSpace 𝕜
h₁ : TopologicalAddGroup 𝕜
h₂ : ContinuousSMul 𝕜 𝕜
h₃ : T2Space 𝕜
ε : ℝ
hε : 0 < ε
ξ₀ : 𝕜
hξ₀ : 0 < ‖ξ₀‖
hξ₀ε : ‖ξ₀‖ < ε
⊢ Metric.closedBall 0 ε ∈ nhds 0

tactic: have : balancedCore 𝕜 ({ξ₀}ᶜ) ∈ @nhds 𝕜 t 0 := balancedCore_mem_nhds_zero this
state_before: case refine'_1.intro.intro
𝕜 : Type u
hnorm : NontriviallyNormedField 𝕜
E : Type v
inst✝¹⁴ : AddCommGroup E
inst✝¹³ : Module 𝕜 E
inst✝¹² : TopologicalSpace E
inst✝¹¹ : TopologicalAddGroup E
inst✝¹⁰ : ContinuousSMul 𝕜 E
F : Type w
inst✝⁹ : AddCommGroup F
inst✝⁸ : Module 𝕜 F
inst✝⁷ : TopologicalSpace F
inst✝⁶ : TopologicalAddGroup F
inst✝⁵ : ContinuousSMul 𝕜 F
F' : Type x
inst✝⁴ : AddCommGroup F'
inst✝³ : Module 𝕜 F'
inst✝² : TopologicalSpace F'
inst✝¹ : TopologicalAddGroup F'
inst✝ : ContinuousSMul 𝕜 F'
t : TopologicalSpace 𝕜
h₁ : TopologicalAddGroup 𝕜
h₂ : ContinuousSMul 𝕜 𝕜
h₃ : T2Space 𝕜
ε : ℝ
hε : 0 < ε
ξ₀ : 𝕜
hξ₀ : 0 < ‖ξ₀‖
hξ₀ε : ‖ξ₀‖ < ε
this : {ξ₀}ᶜ ∈ nhds 0
⊢ Metric.closedBall 0 ε ∈ nhds 0

tactic: refine' mem_of_superset this fun ξ hξ => _
state_before: case refine'_1.intro.intro
𝕜 : Type u
hnorm : NontriviallyNormedField 𝕜
E : Type v
inst✝¹⁴ : AddCommGroup E
inst✝¹³ : Module 𝕜 E
inst✝¹² : TopologicalSpace E
inst✝¹¹ : TopologicalAddGroup E
inst✝¹⁰ : ContinuousSMul 𝕜 E
F : Type w
inst✝⁹ : AddCommGroup F
inst✝⁸ : Module 𝕜 F
inst✝⁷ : TopologicalSpace F
inst✝⁶ : TopologicalAddGroup F
inst✝⁵ : ContinuousSMul 𝕜 F
F' : Type x
inst✝⁴ : AddCommGroup F'
inst✝³ : Module 𝕜 F'
inst✝² : TopologicalSpace F'
inst✝¹ : TopologicalAddGroup F'
inst✝ : ContinuousSMul 𝕜 F'
t : TopologicalSpace 𝕜
h₁ : TopologicalAddGroup 𝕜
h₂ : ContinuousSMul 𝕜 𝕜
h₃ : T2Space 𝕜
ε : ℝ
hε : 0 < ε
ξ₀ : 𝕜
hξ₀ : 0 < ‖ξ₀‖
hξ₀ε : ‖ξ₀‖ < ε
this✝ : {ξ₀}ᶜ ∈ nhds 0
this : balancedCore 𝕜 ({ξ₀}ᶜ) ∈ nhds 0
⊢ Metric.closedBall 0 ε ∈ nhds 0

tactic: by_cases hξ0 : ξ = 0
state_before: case refine'_1.intro.intro
𝕜 : Type u
hnorm : NontriviallyNormedField 𝕜
E : Type v
inst✝¹⁴ : AddCommGroup E
inst✝¹³ : Module 𝕜 E
inst✝¹² : TopologicalSpace E
inst✝¹¹ : TopologicalAddGroup E
inst✝¹⁰ : ContinuousSMul 𝕜 E
F : Type w
inst✝⁹ : AddCommGroup F
inst✝⁸ : Module 𝕜 F
inst✝⁷ : TopologicalSpace F
inst✝⁶ : TopologicalAddGroup F
inst✝⁵ : ContinuousSMul 𝕜 F
F' : Type x
inst✝⁴ : AddCommGroup F'
inst✝³ : Module 𝕜 F'
inst✝² : TopologicalSpace F'
inst✝¹ : TopologicalAddGroup F'
inst✝ : ContinuousSMul 𝕜 F'
t : TopologicalSpace 𝕜
h₁ : TopologicalAddGroup 𝕜
h₂ : ContinuousSMul 𝕜 𝕜
h₃ : T2Space 𝕜
ε : ℝ
hε : 0 < ε
ξ₀ : 𝕜
hξ₀ : 0 < ‖ξ₀‖
hξ₀ε : ‖ξ₀‖ < ε
this✝ : {ξ₀}ᶜ ∈ nhds 0
this : balancedCore 𝕜 ({ξ₀}ᶜ) ∈ nhds 0
ξ : 𝕜
hξ : ξ ∈ balancedCore 𝕜 ({ξ₀}ᶜ)
⊢ ξ ∈ Metric.closedBall 0 ε

tactic: rw [hξ0]
state_before: case pos
𝕜 : Type u
hnorm : NontriviallyNormedField 𝕜
E : Type v
inst✝¹⁴ : AddCommGroup E
inst✝¹³ : Module 𝕜 E
inst✝¹² : TopologicalSpace E
inst✝¹¹ : TopologicalAddGroup E
inst✝¹⁰ : ContinuousSMul 𝕜 E
F : Type w
inst✝⁹ : AddCommGroup F
inst✝⁸ : Module 𝕜 F
inst✝⁷ : TopologicalSpace F
inst✝⁶ : TopologicalAddGroup F
inst✝⁵ : ContinuousSMul 𝕜 F
F' : Type x
inst✝⁴ : AddCommGroup F'
inst✝³ : Module 𝕜 F'
inst✝² : TopologicalSpace F'
inst✝¹ : TopologicalAddGroup F'
inst✝ : ContinuousSMul 𝕜 F'
t : TopologicalSpace 𝕜
h₁ : TopologicalAddGroup 𝕜
h₂ : ContinuousSMul 𝕜 𝕜
h₃ : T2Space 𝕜
ε : ℝ
hε : 0 < ε
ξ₀ : 𝕜
hξ₀ : 0 < ‖ξ₀‖
hξ₀ε : ‖ξ₀‖ < ε
this✝ : {ξ₀}ᶜ ∈ nhds 0
this : balancedCore 𝕜 ({ξ₀}ᶜ) ∈ nhds 0
ξ : 𝕜
hξ : ξ ∈ balancedCore 𝕜 ({ξ₀}ᶜ)
hξ0 : ξ = 0
⊢ ξ ∈ Metric.closedBall 0 ε

tactic: exact Metric.mem_closedBall_self hε.le
state_before: case pos
𝕜 : Type u
hnorm : NontriviallyNormedField 𝕜
E : Type v
inst✝¹⁴ : AddCommGroup E
inst✝¹³ : Module 𝕜 E
inst✝¹² : TopologicalSpace E
inst✝¹¹ : TopologicalAddGroup E
inst✝¹⁰ : ContinuousSMul 𝕜 E
F : Type w
inst✝⁹ : AddCommGroup F
inst✝⁸ : Module 𝕜 F
inst✝⁷ : TopologicalSpace F
inst✝⁶ : TopologicalAddGroup F
inst✝⁵ : ContinuousSMul 𝕜 F
F' : Type x
inst✝⁴ : AddCommGroup F'
inst✝³ : Module 𝕜 F'
inst✝² : TopologicalSpace F'
inst✝¹ : TopologicalAddGroup F'
inst✝ : ContinuousSMul 𝕜 F'
t : TopologicalSpace 𝕜
h₁ : TopologicalAddGroup 𝕜
h₂ : ContinuousSMul 𝕜 𝕜
h₃ : T2Space 𝕜
ε : ℝ
hε : 0 < ε
ξ₀ : 𝕜
hξ₀ : 0 < ‖ξ₀‖
hξ₀ε : ‖ξ₀‖ < ε
this✝ : {ξ₀}ᶜ ∈ nhds 0
this : balancedCore 𝕜 ({ξ₀}ᶜ) ∈ nhds 0
ξ : 𝕜
hξ : ξ ∈ balancedCore 𝕜 ({ξ₀}ᶜ)
hξ0 : ξ = 0
⊢ 0 ∈ Metric.closedBall 0 ε

tactic: rw [mem_closedBall_zero_iff]
state_before: case neg
𝕜 : Type u
hnorm : NontriviallyNormedField 𝕜
E : Type v
inst✝¹⁴ : AddCommGroup E
inst✝¹³ : Module 𝕜 E
inst✝¹² : TopologicalSpace E
inst✝¹¹ : TopologicalAddGroup E
inst✝¹⁰ : ContinuousSMul 𝕜 E
F : Type w
inst✝⁹ : AddCommGroup F
inst✝⁸ : Module 𝕜 F
inst✝⁷ : TopologicalSpace F
inst✝⁶ : TopologicalAddGroup F
inst✝⁵ : ContinuousSMul 𝕜 F
F' : Type x
inst✝⁴ : AddCommGroup F'
inst✝³ : Module 𝕜 F'
inst✝² : TopologicalSpace F'
inst✝¹ : TopologicalAddGroup F'
inst✝ : ContinuousSMul 𝕜 F'
t : TopologicalSpace 𝕜
h₁ : TopologicalAddGroup 𝕜
h₂ : ContinuousSMul 𝕜 𝕜
h₃ : T2Space 𝕜
ε : ℝ
hε : 0 < ε
ξ₀ : 𝕜
hξ₀ : 0 < ‖ξ₀‖
hξ₀ε : ‖ξ₀‖ < ε
this✝ : {ξ₀}ᶜ ∈ nhds 0
this : balancedCore 𝕜 ({ξ₀}ᶜ) ∈ nhds 0
ξ : 𝕜
hξ : ξ ∈ balancedCore 𝕜 ({ξ₀}ᶜ)
hξ0 : ¬ξ = 0
⊢ ξ ∈ Metric.closedBall 0 ε

tactic: by_contra' h
state_before: case neg
𝕜 : Type u
hnorm : NontriviallyNormedField 𝕜
E : Type v
inst✝¹⁴ : AddCommGroup E
inst✝¹³ : Module 𝕜 E
inst✝¹² : TopologicalSpace E
inst✝¹¹ : TopologicalAddGroup E
inst✝¹⁰ : ContinuousSMul 𝕜 E
F : Type w
inst✝⁹ : AddCommGroup F
inst✝⁸ : Module 𝕜 F
inst✝⁷ : TopologicalSpace F
inst✝⁶ : TopologicalAddGroup F
inst✝⁵ : ContinuousSMul 𝕜 F
F' : Type x
inst✝⁴ : AddCommGroup F'
inst✝³ : Module 𝕜 F'
inst✝² : TopologicalSpace F'
inst✝¹ : TopologicalAddGroup F'
inst✝ : ContinuousSMul 𝕜 F'
t : TopologicalSpace 𝕜
h₁ : TopologicalAddGroup 𝕜
h₂ : ContinuousSMul 𝕜 𝕜
h₃ : T2Space 𝕜
ε : ℝ
hε : 0 < ε
ξ₀ : 𝕜
hξ₀ : 0 < ‖ξ₀‖
hξ₀ε : ‖ξ₀‖ < ε
this✝ : {ξ₀}ᶜ ∈ nhds 0
this : balancedCore 𝕜 ({ξ₀}ᶜ) ∈ nhds 0
ξ : 𝕜
hξ : ξ ∈ balancedCore 𝕜 ({ξ₀}ᶜ)
hξ0 : ¬ξ = 0
⊢ ‖ξ‖ ≤ ε

tactic: suffices (ξ₀ * ξ⁻¹) • ξ ∈ balancedCore 𝕜 ({ξ₀}ᶜ) by
  rw [smul_eq_mul 𝕜, mul_assoc, inv_mul_cancel hξ0, mul_one] at this
  exact not_mem_compl_iff.mpr (mem_singleton ξ₀) ((balancedCore_subset _) this)
state_before: case neg
𝕜 : Type u
hnorm : NontriviallyNormedField 𝕜
E : Type v
inst✝¹⁴ : AddCommGroup E
inst✝¹³ : Module 𝕜 E
inst✝¹² : TopologicalSpace E
inst✝¹¹ : TopologicalAddGroup E
inst✝¹⁰ : ContinuousSMul 𝕜 E
F : Type w
inst✝⁹ : AddCommGroup F
inst✝⁸ : Module 𝕜 F
inst✝⁷ : TopologicalSpace F
inst✝⁶ : TopologicalAddGroup F
inst✝⁵ : ContinuousSMul 𝕜 F
F' : Type x
inst✝⁴ : AddCommGroup F'
inst✝³ : Module 𝕜 F'
inst✝² : TopologicalSpace F'
inst✝¹ : TopologicalAddGroup F'
inst✝ : ContinuousSMul 𝕜 F'
t : TopologicalSpace 𝕜
h₁ : TopologicalAddGroup 𝕜
h₂ : ContinuousSMul 𝕜 𝕜
h₃ : T2Space 𝕜
ε : ℝ
hε : 0 < ε
ξ₀ : 𝕜
hξ₀ : 0 < ‖ξ₀‖
hξ₀ε : ‖ξ₀‖ < ε
this✝ : {ξ₀}ᶜ ∈ nhds 0
this : balancedCore 𝕜 ({ξ₀}ᶜ) ∈ nhds 0
ξ : 𝕜
hξ : ξ ∈ balancedCore 𝕜 ({ξ₀}ᶜ)
hξ0 : ¬ξ = 0
h : ε < ‖ξ‖
⊢ False

tactic: refine' (balancedCore_balanced _).smul_mem _ hξ
state_before: case neg
𝕜 : Type u
hnorm : NontriviallyNormedField 𝕜
E : Type v
inst✝¹⁴ : AddCommGroup E
inst✝¹³ : Module 𝕜 E
inst✝¹² : TopologicalSpace E
inst✝¹¹ : TopologicalAddGroup E
inst✝¹⁰ : ContinuousSMul 𝕜 E
F : Type w
inst✝⁹ : AddCommGroup F
inst✝⁸ : Module 𝕜 F
inst✝⁷ : TopologicalSpace F
inst✝⁶ : TopologicalAddGroup F
inst✝⁵ : ContinuousSMul 𝕜 F
F' : Type x
inst✝⁴ : AddCommGroup F'
inst✝³ : Module 𝕜 F'
inst✝² : TopologicalSpace F'
inst✝¹ : TopologicalAddGroup F'
inst✝ : ContinuousSMul 𝕜 F'
t : TopologicalSpace 𝕜
h₁ : TopologicalAddGroup 𝕜
h₂ : ContinuousSMul 𝕜 𝕜
h₃ : T2Space 𝕜
ε : ℝ
hε : 0 < ε
ξ₀ : 𝕜
hξ₀ : 0 < ‖ξ₀‖
hξ₀ε : ‖ξ₀‖ < ε
this✝ : {ξ₀}ᶜ ∈ nhds 0
this : balancedCore 𝕜 ({ξ₀}ᶜ) ∈ nhds 0
ξ : 𝕜
hξ : ξ ∈ balancedCore 𝕜 ({ξ₀}ᶜ)
hξ0 : ¬ξ = 0
h : ε < ‖ξ‖
⊢ (ξ₀ * ξ⁻¹) • ξ ∈ balancedCore 𝕜 ({ξ₀}ᶜ)

tactic: rw [norm_mul, norm_inv, mul_inv_le_iff (norm_pos_iff.mpr hξ0), mul_one]
state_before: case neg
𝕜 : Type u
hnorm : NontriviallyNormedField 𝕜
E : Type v
inst✝¹⁴ : AddCommGroup E
inst✝¹³ : Module 𝕜 E
inst✝¹² : TopologicalSpace E
inst✝¹¹ : TopologicalAddGroup E
inst✝¹⁰ : ContinuousSMul 𝕜 E
F : Type w
inst✝⁹ : AddCommGroup F
inst✝⁸ : Module 𝕜 F
inst✝⁷ : TopologicalSpace F
inst✝⁶ : TopologicalAddGroup F
inst✝⁵ : ContinuousSMul 𝕜 F
F' : Type x
inst✝⁴ : AddCommGroup F'
inst✝³ : Module 𝕜 F'
inst✝² : TopologicalSpace F'
inst✝¹ : TopologicalAddGroup F'
inst✝ : ContinuousSMul 𝕜 F'
t : TopologicalSpace 𝕜
h₁ : TopologicalAddGroup 𝕜
h₂ : ContinuousSMul 𝕜 𝕜
h₃ : T2Space 𝕜
ε : ℝ
hε : 0 < ε
ξ₀ : 𝕜
hξ₀ : 0 < ‖ξ₀‖
hξ₀ε : ‖ξ₀‖ < ε
this✝ : {ξ₀}ᶜ ∈ nhds 0
this : balancedCore 𝕜 ({ξ₀}ᶜ) ∈ nhds 0
ξ : 𝕜
hξ : ξ ∈ balancedCore 𝕜 ({ξ₀}ᶜ)
hξ0 : ¬ξ = 0
h : ε < ‖ξ‖
⊢ ‖ξ₀ * ξ⁻¹‖ ≤ 1

tactic: exact (hξ₀ε.trans h).le
state_before: case neg
𝕜 : Type u
hnorm : NontriviallyNormedField 𝕜
E : Type v
inst✝¹⁴ : AddCommGroup E
inst✝¹³ : Module 𝕜 E
inst✝¹² : TopologicalSpace E
inst✝¹¹ : TopologicalAddGroup E
inst✝¹⁰ : ContinuousSMul 𝕜 E
F : Type w
inst✝⁹ : AddCommGroup F
inst✝⁸ : Module 𝕜 F
inst✝⁷ : TopologicalSpace F
inst✝⁶ : TopologicalAddGroup F
inst✝⁵ : ContinuousSMul 𝕜 F
F' : Type x
inst✝⁴ : AddCommGroup F'
inst✝³ : Module 𝕜 F'
inst✝² : TopologicalSpace F'
inst✝¹ : TopologicalAddGroup F'
inst✝ : ContinuousSMul 𝕜 F'
t : TopologicalSpace 𝕜
h₁ : TopologicalAddGroup 𝕜
h₂ : ContinuousSMul 𝕜 𝕜
h₃ : T2Space 𝕜
ε : ℝ
hε : 0 < ε
ξ₀ : 𝕜
hξ₀ : 0 < ‖ξ₀‖
hξ₀ε : ‖ξ₀‖ < ε
this✝ : {ξ₀}ᶜ ∈ nhds 0
this : balancedCore 𝕜 ({ξ₀}ᶜ) ∈ nhds 0
ξ : 𝕜
hξ : ξ ∈ balancedCore 𝕜 ({ξ₀}ᶜ)
hξ0 : ¬ξ = 0
h : ε < ‖ξ‖
⊢ ‖ξ₀‖ ≤ ‖ξ‖

tactic: rw [smul_eq_mul 𝕜, mul_assoc, inv_mul_cancel hξ0, mul_one] at this
state_before: 𝕜 : Type u
hnorm : NontriviallyNormedField 𝕜
E : Type v
inst✝¹⁴ : AddCommGroup E
inst✝¹³ : Module 𝕜 E
inst✝¹² : TopologicalSpace E
inst✝¹¹ : TopologicalAddGroup E
inst✝¹⁰ : ContinuousSMul 𝕜 E
F : Type w
inst✝⁹ : AddCommGroup F
inst✝⁸ : Module 𝕜 F
inst✝⁷ : TopologicalSpace F
inst✝⁶ : TopologicalAddGroup F
inst✝⁵ : ContinuousSMul 𝕜 F
F' : Type x
inst✝⁴ : AddCommGroup F'
inst✝³ : Module 𝕜 F'
inst✝² : TopologicalSpace F'
inst✝¹ : TopologicalAddGroup F'
inst✝ : ContinuousSMul 𝕜 F'
t : TopologicalSpace 𝕜
h₁ : TopologicalAddGroup 𝕜
h₂ : ContinuousSMul 𝕜 𝕜
h₃ : T2Space 𝕜
ε : ℝ
hε : 0 < ε
ξ₀ : 𝕜
hξ₀ : 0 < ‖ξ₀‖
hξ₀ε : ‖ξ₀‖ < ε
this✝¹ : {ξ₀}ᶜ ∈ nhds 0
this✝ : balancedCore 𝕜 ({ξ₀}ᶜ) ∈ nhds 0
ξ : 𝕜
hξ : ξ ∈ balancedCore 𝕜 ({ξ₀}ᶜ)
hξ0 : ¬ξ = 0
h : ε < ‖ξ‖
this : (ξ₀ * ξ⁻¹) • ξ ∈ balancedCore 𝕜 ({ξ₀}ᶜ)
⊢ False

tactic: exact not_mem_compl_iff.mpr (mem_singleton ξ₀) ((balancedCore_subset _) this)
state_before: 𝕜 : Type u
hnorm : NontriviallyNormedField 𝕜
E : Type v
inst✝¹⁴ : AddCommGroup E
inst✝¹³ : Module 𝕜 E
inst✝¹² : TopologicalSpace E
inst✝¹¹ : TopologicalAddGroup E
inst✝¹⁰ : ContinuousSMul 𝕜 E
F : Type w
inst✝⁹ : AddCommGroup F
inst✝⁸ : Module 𝕜 F
inst✝⁷ : TopologicalSpace F
inst✝⁶ : TopologicalAddGroup F
inst✝⁵ : ContinuousSMul 𝕜 F
F' : Type x
inst✝⁴ : AddCommGroup F'
inst✝³ : Module 𝕜 F'
inst✝² : TopologicalSpace F'
inst✝¹ : TopologicalAddGroup F'
inst✝ : ContinuousSMul 𝕜 F'
t : TopologicalSpace 𝕜
h₁ : TopologicalAddGroup 𝕜
h₂ : ContinuousSMul 𝕜 𝕜
h₃ : T2Space 𝕜
ε : ℝ
hε : 0 < ε
ξ₀ : 𝕜
hξ₀ : 0 < ‖ξ₀‖
hξ₀ε : ‖ξ₀‖ < ε
this✝¹ : {ξ₀}ᶜ ∈ nhds 0
this✝ : balancedCore 𝕜 ({ξ₀}ᶜ) ∈ nhds 0
ξ : 𝕜
hξ : ξ ∈ balancedCore 𝕜 ({ξ₀}ᶜ)
hξ0 : ¬ξ = 0
h : ε < ‖ξ‖
this : ξ₀ ∈ balancedCore 𝕜 ({ξ₀}ᶜ)
⊢ False

tactic: calc
  @nhds 𝕜 hnorm.toUniformSpace.toTopologicalSpace 0 =
      map id (@nhds 𝕜 hnorm.toUniformSpace.toTopologicalSpace 0) :=
    map_id.symm
  _ = map (fun x => id x • (1 : 𝕜)) (@nhds 𝕜 hnorm.toUniformSpace.toTopologicalSpace 0) := by
    conv_rhs =>
      congr
      ext
      rw [smul_eq_mul, mul_one]
  _ ≤ @nhds 𝕜 t ((0 : 𝕜) • (1 : 𝕜)) :=
    (@Tendsto.smul_const _ _ _ hnorm.toUniformSpace.toTopologicalSpace t _ _ _ _ _
      tendsto_id (1 : 𝕜))
  _ = @nhds 𝕜 t 0 := by rw [zero_smul]
state_before: case refine'_2
𝕜 : Type u
hnorm : NontriviallyNormedField 𝕜
E : Type v
inst✝¹⁴ : AddCommGroup E
inst✝¹³ : Module 𝕜 E
inst✝¹² : TopologicalSpace E
inst✝¹¹ : TopologicalAddGroup E
inst✝¹⁰ : ContinuousSMul 𝕜 E
F : Type w
inst✝⁹ : AddCommGroup F
inst✝⁸ : Module 𝕜 F
inst✝⁷ : TopologicalSpace F
inst✝⁶ : TopologicalAddGroup F
inst✝⁵ : ContinuousSMul 𝕜 F
F' : Type x
inst✝⁴ : AddCommGroup F'
inst✝³ : Module 𝕜 F'
inst✝² : TopologicalSpace F'
inst✝¹ : TopologicalAddGroup F'
inst✝ : ContinuousSMul 𝕜 F'
t : TopologicalSpace 𝕜
h₁ : TopologicalAddGroup 𝕜
h₂ : ContinuousSMul 𝕜 𝕜
h₃ : T2Space 𝕜
⊢ nhds 0 ≤ nhds 0

tactic: conv_rhs =>
  congr
  ext
  rw [smul_eq_mul, mul_one]
state_before: 𝕜 : Type u
hnorm : NontriviallyNormedField 𝕜
E : Type v
inst✝¹⁴ : AddCommGroup E
inst✝¹³ : Module 𝕜 E
inst✝¹² : TopologicalSpace E
inst✝¹¹ : TopologicalAddGroup E
inst✝¹⁰ : ContinuousSMul 𝕜 E
F : Type w
inst✝⁹ : AddCommGroup F
inst✝⁸ : Module 𝕜 F
inst✝⁷ : TopologicalSpace F
inst✝⁶ : TopologicalAddGroup F
inst✝⁵ : ContinuousSMul 𝕜 F
F' : Type x
inst✝⁴ : AddCommGroup F'
inst✝³ : Module 𝕜 F'
inst✝² : TopologicalSpace F'
inst✝¹ : TopologicalAddGroup F'
inst✝ : ContinuousSMul 𝕜 F'
t : TopologicalSpace 𝕜
h₁ : TopologicalAddGroup 𝕜
h₂ : ContinuousSMul 𝕜 𝕜
h₃ : T2Space 𝕜
⊢ map id (nhds 0) = map (fun x => id x • 1) (nhds 0)

tactic: rw [zero_smul]
state_before: 𝕜 : Type u
hnorm : NontriviallyNormedField 𝕜
E : Type v
inst✝¹⁴ : AddCommGroup E
inst✝¹³ : Module 𝕜 E
inst✝¹² : TopologicalSpace E
inst✝¹¹ : TopologicalAddGroup E
inst✝¹⁰ : ContinuousSMul 𝕜 E
F : Type w
inst✝⁹ : AddCommGroup F
inst✝⁸ : Module 𝕜 F
inst✝⁷ : TopologicalSpace F
inst✝⁶ : TopologicalAddGroup F
inst✝⁵ : ContinuousSMul 𝕜 F
F' : Type x
inst✝⁴ : AddCommGroup F'
inst✝³ : Module 𝕜 F'
inst✝² : TopologicalSpace F'
inst✝¹ : TopologicalAddGroup F'
inst✝ : ContinuousSMul 𝕜 F'
t : TopologicalSpace 𝕜
h₁ : TopologicalAddGroup 𝕜
h₂ : ContinuousSMul 𝕜 𝕜
h₃ : T2Space 𝕜
⊢ nhds (0 • 1) = nhds 0