Theorem: spectrum.spectralRadius_le_liminf_pow_nnnorm_pow_one_div
File: Mathlib/Analysis/Normed/Algebra/Spectrum.lean

Proof steps:
state_before: 𝕜 : Type u_1
A : Type u_2
inst✝³ : NormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : CompleteSpace A
a : A
⊢ spectralRadius 𝕜 a ≤ liminf (fun n => ↑‖a ^ n‖₊ ^ (1 / ↑n)) atTop
state_after: 𝕜 : Type u_1
A : Type u_2
inst✝³ : NormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : CompleteSpace A
a : A
ε : ℝ≥0∞
hε : ε < 1
⊢ ε * spectralRadius 𝕜 a ≤ liminf (fun n => ↑‖a ^ n‖₊ ^ (1 / ↑n)) atTop
tactic: refine ENNReal.le_of_forall_lt_one_mul_le fun ε hε => ?_
state_before: 𝕜 : Type u_1
A : Type u_2
inst✝³ : NormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : CompleteSpace A
a : A
ε : ℝ≥0∞
hε : ε < 1
⊢ ε * spectralRadius 𝕜 a ≤ liminf (fun n => ↑‖a ^ n‖₊ ^ (1 / ↑n)) atTop
state_after: case pos
𝕜 : Type u_1
A : Type u_2
inst✝³ : NormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : CompleteSpace A
a : A
ε : ℝ≥0∞
hε : ε < 1
h : ε = 0
⊢ ε * spectralRadius 𝕜 a ≤ liminf (fun n => ↑‖a ^ n‖₊ ^ (1 / ↑n)) atTop

case neg
𝕜 : Type u_1
A : Type u_2
inst✝³ : NormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : CompleteSpace A
a : A
ε : ℝ≥0∞
hε : ε < 1
h : ¬ε = 0
⊢ ε * spectralRadius 𝕜 a ≤ liminf (fun n => ↑‖a ^ n‖₊ ^ (1 / ↑n)) atTop
tactic: by_cases h : ε = 0
state_before: case neg
𝕜 : Type u_1
A : Type u_2
inst✝³ : NormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : CompleteSpace A
a : A
ε : ℝ≥0∞
hε : ε < 1
h : ¬ε = 0
⊢ ε * spectralRadius 𝕜 a ≤ liminf (fun n => ↑‖a ^ n‖₊ ^ (1 / ↑n)) atTop
state_after: case neg
𝕜 : Type u_1
A : Type u_2
inst✝³ : NormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : CompleteSpace A
a : A
ε : ℝ≥0∞
hε : ε < 1
h : ¬ε = 0
hε' : ε⁻¹ ≠ ⊤
⊢ ε * spectralRadius 𝕜 a ≤ liminf (fun n => ↑‖a ^ n‖₊ ^ (1 / ↑n)) atTop
tactic: have hε' : ε⁻¹ ≠ ∞ := fun h' =>
    h (by simpa only [inv_inv, inv_top] using congr_arg (fun x : ℝ≥0∞ => x⁻¹) h')
state_before: case neg
𝕜 : Type u_1
A : Type u_2
inst✝³ : NormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : CompleteSpace A
a : A
ε : ℝ≥0∞
hε : ε < 1
h : ¬ε = 0
hε' : ε⁻¹ ≠ ⊤
⊢ ε * spectralRadius 𝕜 a ≤ liminf (fun n => ↑‖a ^ n‖₊ ^ (1 / ↑n)) atTop
state_after: case neg
𝕜 : Type u_1
A : Type u_2
inst✝³ : NormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : CompleteSpace A
a : A
ε : ℝ≥0∞
hε : ε < 1
h : ¬ε = 0
hε' : ε⁻¹ ≠ ⊤
⊢ spectralRadius 𝕜 a ≤ ⨆ i, (⨅ i_1, ↑‖a ^ (i_1 + i)‖₊ ^ (1 / ↑(i_1 + i))) * ε⁻¹
tactic: simp only [ENNReal.mul_le_iff_le_inv h (hε.trans_le le_top).ne, mul_comm ε⁻¹,
    liminf_eq_iSup_iInf_of_nat', ENNReal.iSup_mul]
state_before: case neg
𝕜 : Type u_1
A : Type u_2
inst✝³ : NormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : CompleteSpace A
a : A
ε : ℝ≥0∞
hε : ε < 1
h : ¬ε = 0
hε' : ε⁻¹ ≠ ⊤
⊢ spectralRadius 𝕜 a ≤ ⨆ i, (⨅ i_1, ↑‖a ^ (i_1 + i)‖₊ ^ (1 / ↑(i_1 + i))) * ε⁻¹
state_after: case neg
𝕜 : Type u_1
A : Type u_2
inst✝³ : NormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : CompleteSpace A
a : A
ε : ℝ≥0∞
hε : ε < 1
h : ¬ε = 0
hε' : ε⁻¹ ≠ ⊤
⊢ spectralRadius 𝕜 a ≤ ⨆ i, ⨅ i_1, ↑‖a ^ (i_1 + i)‖₊ ^ (1 / ↑(i_1 + i)) * ε⁻¹
tactic: conv_rhs => arg 1; intro i; rw [ENNReal.iInf_mul hε']
state_before: case neg
𝕜 : Type u_1
A : Type u_2
inst✝³ : NormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : CompleteSpace A
a : A
ε : ℝ≥0∞
hε : ε < 1
h : ¬ε = 0
hε' : ε⁻¹ ≠ ⊤
⊢ spectralRadius 𝕜 a ≤ ⨆ i, ⨅ i_1, ↑‖a ^ (i_1 + i)‖₊ ^ (1 / ↑(i_1 + i)) * ε⁻¹
state_after: case neg
𝕜 : Type u_1
A : Type u_2
inst✝³ : NormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : CompleteSpace A
a : A
ε : ℝ≥0∞
hε : 1 < ε⁻¹
h : ¬ε = 0
hε' : ε⁻¹ ≠ ⊤
⊢ spectralRadius 𝕜 a ≤ ⨆ i, ⨅ i_1, ↑‖a ^ (i_1 + i)‖₊ ^ (1 / ↑(i_1 + i)) * ε⁻¹
tactic: rw [← ENNReal.inv_lt_inv, inv_one] at hε
state_before: case neg
𝕜 : Type u_1
A : Type u_2
inst✝³ : NormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : CompleteSpace A
a : A
ε : ℝ≥0∞
hε : 1 < ε⁻¹
h : ¬ε = 0
hε' : ε⁻¹ ≠ ⊤
⊢ spectralRadius 𝕜 a ≤ ⨆ i, ⨅ i_1, ↑‖a ^ (i_1 + i)‖₊ ^ (1 / ↑(i_1 + i)) * ε⁻¹
state_after: case neg.intro
𝕜 : Type u_1
A : Type u_2
inst✝³ : NormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : CompleteSpace A
a : A
ε : ℝ≥0∞
hε : 1 < ε⁻¹
h : ¬ε = 0
hε' : ε⁻¹ ≠ ⊤
N : ℕ
hN : ∀ b ≥ N, ↑‖1‖₊ ^ (1 / ↑b) ≤ ε⁻¹
⊢ spectralRadius 𝕜 a ≤ ⨆ i, ⨅ i_1, ↑‖a ^ (i_1 + i)‖₊ ^ (1 / ↑(i_1 + i)) * ε⁻¹
tactic: obtain ⟨N, hN⟩ := eventually_atTop.mp
    (ENNReal.eventually_pow_one_div_le (ENNReal.coe_ne_top : ↑‖(1 : A)‖₊ ≠ ∞) hε)
state_before: case neg.intro
𝕜 : Type u_1
A : Type u_2
inst✝³ : NormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : CompleteSpace A
a : A
ε : ℝ≥0∞
hε : 1 < ε⁻¹
h : ¬ε = 0
hε' : ε⁻¹ ≠ ⊤
N : ℕ
hN : ∀ b ≥ N, ↑‖1‖₊ ^ (1 / ↑b) ≤ ε⁻¹
⊢ spectralRadius 𝕜 a ≤ ⨆ i, ⨅ i_1, ↑‖a ^ (i_1 + i)‖₊ ^ (1 / ↑(i_1 + i)) * ε⁻¹
state_after: case neg.intro
𝕜 : Type u_1
A : Type u_2
inst✝³ : NormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : CompleteSpace A
a : A
ε : ℝ≥0∞
hε : 1 < ε⁻¹
h : ¬ε = 0
hε' : ε⁻¹ ≠ ⊤
N : ℕ
hN : ∀ b ≥ N, ↑‖1‖₊ ^ (1 / ↑b) ≤ ε⁻¹
⊢ spectralRadius 𝕜 a ≤ ⨅ i, ↑‖a ^ (i + (N + 1))‖₊ ^ (1 / ↑(i + (N + 1))) * ε⁻¹
tactic: refine le_trans ?_ (le_iSup _ (N + 1))
state_before: case neg.intro
𝕜 : Type u_1
A : Type u_2
inst✝³ : NormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : CompleteSpace A
a : A
ε : ℝ≥0∞
hε : 1 < ε⁻¹
h : ¬ε = 0
hε' : ε⁻¹ ≠ ⊤
N : ℕ
hN : ∀ b ≥ N, ↑‖1‖₊ ^ (1 / ↑b) ≤ ε⁻¹
⊢ spectralRadius 𝕜 a ≤ ⨅ i, ↑‖a ^ (i + (N + 1))‖₊ ^ (1 / ↑(i + (N + 1))) * ε⁻¹
state_after: case neg.intro
𝕜 : Type u_1
A : Type u_2
inst✝³ : NormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : CompleteSpace A
a : A
ε : ℝ≥0∞
hε : 1 < ε⁻¹
h : ¬ε = 0
hε' : ε⁻¹ ≠ ⊤
N : ℕ
hN : ∀ b ≥ N, ↑‖1‖₊ ^ (1 / ↑b) ≤ ε⁻¹
n : ℕ
⊢ spectralRadius 𝕜 a ≤ ↑‖a ^ (n + (N + 1))‖₊ ^ (1 / ↑(n + (N + 1))) * ε⁻¹
tactic: refine le_iInf fun n => ?_
state_before: case neg.intro
𝕜 : Type u_1
A : Type u_2
inst✝³ : NormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : CompleteSpace A
a : A
ε : ℝ≥0∞
hε : 1 < ε⁻¹
h : ¬ε = 0
hε' : ε⁻¹ ≠ ⊤
N : ℕ
hN : ∀ b ≥ N, ↑‖1‖₊ ^ (1 / ↑b) ≤ ε⁻¹
n : ℕ
⊢ spectralRadius 𝕜 a ≤ ↑‖a ^ (n + (N + 1))‖₊ ^ (1 / ↑(n + (N + 1))) * ε⁻¹
state_after: case neg.intro
𝕜 : Type u_1
A : Type u_2
inst✝³ : NormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : CompleteSpace A
a : A
ε : ℝ≥0∞
hε : 1 < ε⁻¹
h : ¬ε = 0
hε' : ε⁻¹ ≠ ⊤
N : ℕ
hN : ∀ b ≥ N, ↑‖1‖₊ ^ (1 / ↑b) ≤ ε⁻¹
n : ℕ
⊢ spectralRadius 𝕜 a ≤ ↑‖a ^ (n + N + 1)‖₊ ^ (1 / ↑(n + N + 1)) * ε⁻¹
tactic: simp only [← add_assoc]
state_before: case neg.intro
𝕜 : Type u_1
A : Type u_2
inst✝³ : NormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : CompleteSpace A
a : A
ε : ℝ≥0∞
hε : 1 < ε⁻¹
h : ¬ε = 0
hε' : ε⁻¹ ≠ ⊤
N : ℕ
hN : ∀ b ≥ N, ↑‖1‖₊ ^ (1 / ↑b) ≤ ε⁻¹
n : ℕ
⊢ spectralRadius 𝕜 a ≤ ↑‖a ^ (n + N + 1)‖₊ ^ (1 / ↑(n + N + 1)) * ε⁻¹
state_after: case neg.intro
𝕜 : Type u_1
A : Type u_2
inst✝³ : NormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : CompleteSpace A
a : A
ε : ℝ≥0∞
hε : 1 < ε⁻¹
h : ¬ε = 0
hε' : ε⁻¹ ≠ ⊤
N : ℕ
hN : ∀ b ≥ N, ↑‖1‖₊ ^ (1 / ↑b) ≤ ε⁻¹
n : ℕ
⊢ ↑‖a ^ (n + N + 1)‖₊ ^ (1 / (↑(n + N) + 1)) * ↑‖1‖₊ ^ (1 / (↑(n + N) + 1)) ≤
    ↑‖a ^ (n + N + 1)‖₊ ^ (1 / ↑(n + N + 1)) * ε⁻¹
tactic: refine (spectralRadius_le_pow_nnnorm_pow_one_div 𝕜 a (n + N)).trans ?_
state_before: case neg.intro
𝕜 : Type u_1
A : Type u_2
inst✝³ : NormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : CompleteSpace A
a : A
ε : ℝ≥0∞
hε : 1 < ε⁻¹
h : ¬ε = 0
hε' : ε⁻¹ ≠ ⊤
N : ℕ
hN : ∀ b ≥ N, ↑‖1‖₊ ^ (1 / ↑b) ≤ ε⁻¹
n : ℕ
⊢ ↑‖a ^ (n + N + 1)‖₊ ^ (1 / (↑(n + N) + 1)) * ↑‖1‖₊ ^ (1 / (↑(n + N) + 1)) ≤
    ↑‖a ^ (n + N + 1)‖₊ ^ (1 / ↑(n + N + 1)) * ε⁻¹
state_after: case neg.intro
𝕜 : Type u_1
A : Type u_2
inst✝³ : NormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : CompleteSpace A
a : A
ε : ℝ≥0∞
hε : 1 < ε⁻¹
h : ¬ε = 0
hε' : ε⁻¹ ≠ ⊤
N : ℕ
hN : ∀ b ≥ N, ↑‖1‖₊ ^ (1 / ↑b) ≤ ε⁻¹
n : ℕ
⊢ ↑‖a ^ (n + N + 1)‖₊ ^ (1 / ↑(n + N + 1)) * ↑‖1‖₊ ^ (1 / ↑(n + N + 1)) ≤ ↑‖a ^ (n + N + 1)‖₊ ^ (1 / ↑(n + N + 1)) * ε⁻¹
tactic: norm_cast
state_before: case neg.intro
𝕜 : Type u_1
A : Type u_2
inst✝³ : NormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : CompleteSpace A
a : A
ε : ℝ≥0∞
hε : 1 < ε⁻¹
h : ¬ε = 0
hε' : ε⁻¹ ≠ ⊤
N : ℕ
hN : ∀ b ≥ N, ↑‖1‖₊ ^ (1 / ↑b) ≤ ε⁻¹
n : ℕ
⊢ ↑‖a ^ (n + N + 1)‖₊ ^ (1 / ↑(n + N + 1)) * ↑‖1‖₊ ^ (1 / ↑(n + N + 1)) ≤ ↑‖a ^ (n + N + 1)‖₊ ^ (1 / ↑(n + N + 1)) * ε⁻¹
state_after: no goals
tactic: exact mul_le_mul_left' (hN (n + N + 1) (by omega)) _