Theorem: QuasispectrumRestricts.cfcₙ_eq_restrict
File: Mathlib/Analysis/CstarAlgebra/ContinuousFunctionalCalculus/Restrict.lean

Proof steps:
state_before: R : Type u_1
S : Type u_2
A : Type u_3
p q : A → Prop
inst✝²⁷ : Semifield R
inst✝²⁶ : StarRing R
inst✝²⁵ : MetricSpace R
inst✝²⁴ : TopologicalSemiring R
inst✝²³ : ContinuousStar R
inst✝²² : Field S
inst✝²¹ : StarRing S
inst✝²⁰ : MetricSpace S
inst✝¹⁹ : TopologicalRing S
inst✝¹⁸ : ContinuousStar S
inst✝¹⁷ : TopologicalSpace A
inst✝¹⁶ : NonUnitalRing A
inst✝¹⁵ : StarRing A
inst✝¹⁴ : Module S A
inst✝¹³ : IsScalarTower S A A
inst✝¹² : SMulCommClass S A A
inst✝¹¹ : NonUnitalContinuousFunctionalCalculus S q
inst✝¹⁰ : Algebra R S
inst✝⁹ : Module R A
inst✝⁸ : IsScalarTower R S A
inst✝⁷ : StarModule R S
inst✝⁶ : ContinuousSMul R S
inst✝⁵ : CompleteSpace R
inst✝⁴ : IsScalarTower R A A
inst✝³ : SMulCommClass R A A
inst✝² : NonUnitalContinuousFunctionalCalculus R p
inst✝¹ : UniqueNonUnitalContinuousFunctionalCalculus R A
f : C(S, R)
halg : UniformEmbedding ⇑(algebraMap R S)
a : A
hpa : p a
hqa : q a
h : QuasispectrumRestricts a ⇑f
inst✝ : CompactSpace ↑(σₙ S a)
g : R → R
⊢ cfcₙ g a = cfcₙ (fun x => (algebraMap R S) (g (f x))) a
state_after: case pos
R : Type u_1
S : Type u_2
A : Type u_3
p q : A → Prop
inst✝²⁷ : Semifield R
inst✝²⁶ : StarRing R
inst✝²⁵ : MetricSpace R
inst✝²⁴ : TopologicalSemiring R
inst✝²³ : ContinuousStar R
inst✝²² : Field S
inst✝²¹ : StarRing S
inst✝²⁰ : MetricSpace S
inst✝¹⁹ : TopologicalRing S
inst✝¹⁸ : ContinuousStar S
inst✝¹⁷ : TopologicalSpace A
inst✝¹⁶ : NonUnitalRing A
inst✝¹⁵ : StarRing A
inst✝¹⁴ : Module S A
inst✝¹³ : IsScalarTower S A A
inst✝¹² : SMulCommClass S A A
inst✝¹¹ : NonUnitalContinuousFunctionalCalculus S q
inst✝¹⁰ : Algebra R S
inst✝⁹ : Module R A
inst✝⁸ : IsScalarTower R S A
inst✝⁷ : StarModule R S
inst✝⁶ : ContinuousSMul R S
inst✝⁵ : CompleteSpace R
inst✝⁴ : IsScalarTower R A A
inst✝³ : SMulCommClass R A A
inst✝² : NonUnitalContinuousFunctionalCalculus R p
inst✝¹ : UniqueNonUnitalContinuousFunctionalCalculus R A
f : C(S, R)
halg : UniformEmbedding ⇑(algebraMap R S)
a : A
hpa : p a
hqa : q a
h : QuasispectrumRestricts a ⇑f
inst✝ : CompactSpace ↑(σₙ S a)
g : R → R
hg : ContinuousOn g (σₙ R a) ∧ g 0 = 0
⊢ cfcₙ g a = cfcₙ (fun x => (algebraMap R S) (g (f x))) a

case neg
R : Type u_1
S : Type u_2
A : Type u_3
p q : A → Prop
inst✝²⁷ : Semifield R
inst✝²⁶ : StarRing R
inst✝²⁵ : MetricSpace R
inst✝²⁴ : TopologicalSemiring R
inst✝²³ : ContinuousStar R
inst✝²² : Field S
inst✝²¹ : StarRing S
inst✝²⁰ : MetricSpace S
inst✝¹⁹ : TopologicalRing S
inst✝¹⁸ : ContinuousStar S
inst✝¹⁷ : TopologicalSpace A
inst✝¹⁶ : NonUnitalRing A
inst✝¹⁵ : StarRing A
inst✝¹⁴ : Module S A
inst✝¹³ : IsScalarTower S A A
inst✝¹² : SMulCommClass S A A
inst✝¹¹ : NonUnitalContinuousFunctionalCalculus S q
inst✝¹⁰ : Algebra R S
inst✝⁹ : Module R A
inst✝⁸ : IsScalarTower R S A
inst✝⁷ : StarModule R S
inst✝⁶ : ContinuousSMul R S
inst✝⁵ : CompleteSpace R
inst✝⁴ : IsScalarTower R A A
inst✝³ : SMulCommClass R A A
inst✝² : NonUnitalContinuousFunctionalCalculus R p
inst✝¹ : UniqueNonUnitalContinuousFunctionalCalculus R A
f : C(S, R)
halg : UniformEmbedding ⇑(algebraMap R S)
a : A
hpa : p a
hqa : q a
h : QuasispectrumRestricts a ⇑f
inst✝ : CompactSpace ↑(σₙ S a)
g : R → R
hg : ¬(ContinuousOn g (σₙ R a) ∧ g 0 = 0)
⊢ cfcₙ g a = cfcₙ (fun x => (algebraMap R S) (g (f x))) a
tactic: by_cases hg : ContinuousOn g (σₙ R a) ∧ g 0 = 0