Theorem: SpectrumRestricts.spectralRadius_eq
File: Mathlib/Analysis/Normed/Algebra/Spectrum.lean

Proof steps:
state_before: 𝕜 : Type u_1
A✝ : Type u_2
𝕜₁ : Type u_3
𝕜₂ : Type u_4
A : Type u_5
inst✝⁶ : NormedField 𝕜₁
inst✝⁵ : NormedField 𝕜₂
inst✝⁴ : NormedRing A
inst✝³ : NormedAlgebra 𝕜₁ A
inst✝² : NormedAlgebra 𝕜₂ A
inst✝¹ : NormedAlgebra 𝕜₁ 𝕜₂
inst✝ : IsScalarTower 𝕜₁ 𝕜₂ A
f : 𝕜₂ → 𝕜₁
a : A
h : SpectrumRestricts a f
⊢ spectralRadius 𝕜₁ a = spectralRadius 𝕜₂ a
state_after: 𝕜 : Type u_1
A✝ : Type u_2
𝕜₁ : Type u_3
𝕜₂ : Type u_4
A : Type u_5
inst✝⁶ : NormedField 𝕜₁
inst✝⁵ : NormedField 𝕜₂
inst✝⁴ : NormedRing A
inst✝³ : NormedAlgebra 𝕜₁ A
inst✝² : NormedAlgebra 𝕜₂ A
inst✝¹ : NormedAlgebra 𝕜₁ 𝕜₂
inst✝ : IsScalarTower 𝕜₁ 𝕜₂ A
f : 𝕜₂ → 𝕜₁
a : A
h : SpectrumRestricts a f
⊢ ⨆ k ∈ spectrum 𝕜₁ a, ↑‖k‖₊ = ⨆ k ∈ spectrum 𝕜₂ a, ↑‖k‖₊
tactic: rw [spectralRadius, spectralRadius]
state_before: 𝕜 : Type u_1
A✝ : Type u_2
𝕜₁ : Type u_3
𝕜₂ : Type u_4
A : Type u_5
inst✝⁶ : NormedField 𝕜₁
inst✝⁵ : NormedField 𝕜₂
inst✝⁴ : NormedRing A
inst✝³ : NormedAlgebra 𝕜₁ A
inst✝² : NormedAlgebra 𝕜₂ A
inst✝¹ : NormedAlgebra 𝕜₁ 𝕜₂
inst✝ : IsScalarTower 𝕜₁ 𝕜₂ A
f : 𝕜₂ → 𝕜₁
a : A
h : SpectrumRestricts a f
⊢ ⨆ k ∈ spectrum 𝕜₁ a, ↑‖k‖₊ = ⨆ k ∈ spectrum 𝕜₂ a, ↑‖k‖₊
state_after: 𝕜 : Type u_1
A✝ : Type u_2
𝕜₁ : Type u_3
𝕜₂ : Type u_4
A : Type u_5
inst✝⁶ : NormedField 𝕜₁
inst✝⁵ : NormedField 𝕜₂
inst✝⁴ : NormedRing A
inst✝³ : NormedAlgebra 𝕜₁ A
inst✝² : NormedAlgebra 𝕜₂ A
inst✝¹ : NormedAlgebra 𝕜₁ 𝕜₂
inst✝ : IsScalarTower 𝕜₁ 𝕜₂ A
f : 𝕜₂ → 𝕜₁
a : A
h : SpectrumRestricts a f
this : ∀ (x : 𝕜₁), ‖(algebraMap 𝕜₁ 𝕜₂) x‖₊ = ‖x‖₊
⊢ ⨆ k ∈ spectrum 𝕜₁ a, ↑‖k‖₊ = ⨆ k ∈ spectrum 𝕜₂ a, ↑‖k‖₊
tactic: have := algebraMap_isometry 𝕜₁ 𝕜₂ |>.nnnorm_map_of_map_zero (map_zero _)
state_before: 𝕜 : Type u_1
A✝ : Type u_2
𝕜₁ : Type u_3
𝕜₂ : Type u_4
A : Type u_5
inst✝⁶ : NormedField 𝕜₁
inst✝⁵ : NormedField 𝕜₂
inst✝⁴ : NormedRing A
inst✝³ : NormedAlgebra 𝕜₁ A
inst✝² : NormedAlgebra 𝕜₂ A
inst✝¹ : NormedAlgebra 𝕜₁ 𝕜₂
inst✝ : IsScalarTower 𝕜₁ 𝕜₂ A
f : 𝕜₂ → 𝕜₁
a : A
h : SpectrumRestricts a f
this : ∀ (x : 𝕜₁), ‖(algebraMap 𝕜₁ 𝕜₂) x‖₊ = ‖x‖₊
⊢ ⨆ k ∈ spectrum 𝕜₁ a, ↑‖k‖₊ = ⨆ k ∈ spectrum 𝕜₂ a, ↑‖k‖₊
state_after: case a
𝕜 : Type u_1
A✝ : Type u_2
𝕜₁ : Type u_3
𝕜₂ : Type u_4
A : Type u_5
inst✝⁶ : NormedField 𝕜₁
inst✝⁵ : NormedField 𝕜₂
inst✝⁴ : NormedRing A
inst✝³ : NormedAlgebra 𝕜₁ A
inst✝² : NormedAlgebra 𝕜₂ A
inst✝¹ : NormedAlgebra 𝕜₁ 𝕜₂
inst✝ : IsScalarTower 𝕜₁ 𝕜₂ A
f : 𝕜₂ → 𝕜₁
a : A
h : SpectrumRestricts a f
this : ∀ (x : 𝕜₁), ‖(algebraMap 𝕜₁ 𝕜₂) x‖₊ = ‖x‖₊
⊢ ⨆ k ∈ spectrum 𝕜₁ a, ↑‖k‖₊ ≤ ⨆ k ∈ spectrum 𝕜₂ a, ↑‖k‖₊

case a
𝕜 : Type u_1
A✝ : Type u_2
𝕜₁ : Type u_3
𝕜₂ : Type u_4
A : Type u_5
inst✝⁶ : NormedField 𝕜₁
inst✝⁵ : NormedField 𝕜₂
inst✝⁴ : NormedRing A
inst✝³ : NormedAlgebra 𝕜₁ A
inst✝² : NormedAlgebra 𝕜₂ A
inst✝¹ : NormedAlgebra 𝕜₁ 𝕜₂
inst✝ : IsScalarTower 𝕜₁ 𝕜₂ A
f : 𝕜₂ → 𝕜₁
a : A
h : SpectrumRestricts a f
this : ∀ (x : 𝕜₁), ‖(algebraMap 𝕜₁ 𝕜₂) x‖₊ = ‖x‖₊
⊢ ⨆ k ∈ spectrum 𝕜₂ a, ↑‖k‖₊ ≤ ⨆ k ∈ spectrum 𝕜₁ a, ↑‖k‖₊
tactic: apply le_antisymm
state_before: case a
𝕜 : Type u_1
A✝ : Type u_2
𝕜₁ : Type u_3
𝕜₂ : Type u_4
A : Type u_5
inst✝⁶ : NormedField 𝕜₁
inst✝⁵ : NormedField 𝕜₂
inst✝⁴ : NormedRing A
inst✝³ : NormedAlgebra 𝕜₁ A
inst✝² : NormedAlgebra 𝕜₂ A
inst✝¹ : NormedAlgebra 𝕜₁ 𝕜₂
inst✝ : IsScalarTower 𝕜₁ 𝕜₂ A
f : 𝕜₂ → 𝕜₁
a : A
h : SpectrumRestricts a f
this : ∀ (x : 𝕜₁), ‖(algebraMap 𝕜₁ 𝕜₂) x‖₊ = ‖x‖₊
⊢ ⨆ k ∈ spectrum 𝕜₁ a, ↑‖k‖₊ ≤ ⨆ k ∈ spectrum 𝕜₂ a, ↑‖k‖₊

case a
𝕜 : Type u_1
A✝ : Type u_2
𝕜₁ : Type u_3
𝕜₂ : Type u_4
A : Type u_5
inst✝⁶ : NormedField 𝕜₁
inst✝⁵ : NormedField 𝕜₂
inst✝⁴ : NormedRing A
inst✝³ : NormedAlgebra 𝕜₁ A
inst✝² : NormedAlgebra 𝕜₂ A
inst✝¹ : NormedAlgebra 𝕜₁ 𝕜₂
inst✝ : IsScalarTower 𝕜₁ 𝕜₂ A
f : 𝕜₂ → 𝕜₁
a : A
h : SpectrumRestricts a f
this : ∀ (x : 𝕜₁), ‖(algebraMap 𝕜₁ 𝕜₂) x‖₊ = ‖x‖₊
⊢ ⨆ k ∈ spectrum 𝕜₂ a, ↑‖k‖₊ ≤ ⨆ k ∈ spectrum 𝕜₁ a, ↑‖k‖₊
state_after: 𝕜 : Type u_1
A✝ : Type u_2
𝕜₁ : Type u_3
𝕜₂ : Type u_4
A : Type u_5
inst✝⁶ : NormedField 𝕜₁
inst✝⁵ : NormedField 𝕜₂
inst✝⁴ : NormedRing A
inst✝³ : NormedAlgebra 𝕜₁ A
inst✝² : NormedAlgebra 𝕜₂ A
inst✝¹ : NormedAlgebra 𝕜₁ 𝕜₂
inst✝ : IsScalarTower 𝕜₁ 𝕜₂ A
f : 𝕜₂ → 𝕜₁
a : A
h : SpectrumRestricts a f
this : ∀ (x : 𝕜₁), ‖(algebraMap 𝕜₁ 𝕜₂) x‖₊ = ‖x‖₊
x : 𝕜₁
hx : x ∈ spectrum 𝕜₁ a
⊢ ↑‖x‖₊ ≤ ⨆ k ∈ spectrum 𝕜₂ a, ↑‖k‖₊

𝕜 : Type u_1
A✝ : Type u_2
𝕜₁ : Type u_3
𝕜₂ : Type u_4
A : Type u_5
inst✝⁶ : NormedField 𝕜₁
inst✝⁵ : NormedField 𝕜₂
inst✝⁴ : NormedRing A
inst✝³ : NormedAlgebra 𝕜₁ A
inst✝² : NormedAlgebra 𝕜₂ A
inst✝¹ : NormedAlgebra 𝕜₁ 𝕜₂
inst✝ : IsScalarTower 𝕜₁ 𝕜₂ A
f : 𝕜₂ → 𝕜₁
a : A
h : SpectrumRestricts a f
this : ∀ (x : 𝕜₁), ‖(algebraMap 𝕜₁ 𝕜₂) x‖₊ = ‖x‖₊
x : 𝕜₂
hx : x ∈ spectrum 𝕜₂ a
⊢ ↑‖x‖₊ ≤ ⨆ k ∈ spectrum 𝕜₁ a, ↑‖k‖₊
tactic: all_goals apply iSup₂_le fun x hx ↦ ?_