-- Mathlib/Analysis/CStarAlgebra/ContinuousFunctionalCalculus/Instances.lean
lemma isClosedEmbedding_cfcₙAux : IsClosedEmbedding (cfcₙAux hp₁ a ha)

Proof state:
𝕜 : Type u_1
A : Type u_2
inst✝⁷ : RCLike 𝕜
inst✝⁶ : NonUnitalNormedRing A
inst✝⁵ : StarRing A
inst✝⁴ : NormedSpace 𝕜 A
inst✝³ : IsScalarTower 𝕜 A A
inst✝² : SMulCommClass 𝕜 A A
inst✝¹ : StarModule 𝕜 A
p : A → Prop
p₁ : Unitization 𝕜 A → Prop
hp₁ : ∀ {x : A}, p₁ ↑x ↔ p x
a : A
ha : p a
inst✝ : ContinuousFunctionalCalculus 𝕜 p₁
⊢ IsClosedEmbedding ⇑(cfcₙAux ⋯ a ha)

Tactic:
simp only [cfcₙAux, NonUnitalStarAlgHom.coe_comp]

Result:
𝕜 : Type u_1
A : Type u_2
inst✝⁷ : RCLike 𝕜
inst✝⁶ : NonUnitalNormedRing A
inst✝⁵ : StarRing A
inst✝⁴ : NormedSpace 𝕜 A
inst✝³ : IsScalarTower 𝕜 A A
inst✝² : SMulCommClass 𝕜 A A
inst✝¹ : StarModule 𝕜 A
p : A → Prop
p₁ : Unitization 𝕜 A → Prop
hp₁ : ∀ {x : A}, p₁ ↑x ↔ p x
a : A
ha : p a
inst✝ : ContinuousFunctionalCalculus 𝕜 p₁
⊢ IsClosedEmbedding
    ((⇑↑(cfcHom ⋯) ∘ ⇑↑(Homeomorph.compStarAlgEquiv' 𝕜 𝕜 (Homeomorph.setCongr ⋯))) ∘
      ⇑ContinuousMapZero.toContinuousMapHom)

Proof state:
𝕜 : Type u_1
A : Type u_2
inst✝⁷ : RCLike 𝕜
inst✝⁶ : NonUnitalNormedRing A
inst✝⁵ : StarRing A
inst✝⁴ : NormedSpace 𝕜 A
inst✝³ : IsScalarTower 𝕜 A A
inst✝² : SMulCommClass 𝕜 A A
inst✝¹ : StarModule 𝕜 A
p : A → Prop
p₁ : Unitization 𝕜 A → Prop
hp₁ : ∀ {x : A}, p₁ ↑x ↔ p x
a : A
ha : p a
inst✝ : ContinuousFunctionalCalculus 𝕜 p₁
⊢ IsClosedEmbedding
    ((⇑↑(cfcHom ⋯) ∘ ⇑↑(Homeomorph.compStarAlgEquiv' 𝕜 𝕜 (Homeomorph.setCongr ⋯))) ∘
      ⇑ContinuousMapZero.toContinuousMapHom)

Tactic:
refine ((cfcHom_isClosedEmbedding (hp₁.mpr ha)).comp ?_).comp
  ContinuousMapZero.isClosedEmbedding_toContinuousMap

Result:
𝕜 : Type u_1
A : Type u_2
inst✝⁷ : RCLike 𝕜
inst✝⁶ : NonUnitalNormedRing A
inst✝⁵ : StarRing A
inst✝⁴ : NormedSpace 𝕜 A
inst✝³ : IsScalarTower 𝕜 A A
inst✝² : SMulCommClass 𝕜 A A
inst✝¹ : StarModule 𝕜 A
p : A → Prop
p₁ : Unitization 𝕜 A → Prop
hp₁ : ∀ {x : A}, p₁ ↑x ↔ p x
a : A
ha : p a
inst✝ : ContinuousFunctionalCalculus 𝕜 p₁
⊢ IsClosedEmbedding ⇑↑(Homeomorph.compStarAlgEquiv' 𝕜 𝕜 (Homeomorph.setCongr ⋯))

Proof state:
𝕜 : Type u_1
A : Type u_2
inst✝⁷ : RCLike 𝕜
inst✝⁶ : NonUnitalNormedRing A
inst✝⁵ : StarRing A
inst✝⁴ : NormedSpace 𝕜 A
inst✝³ : IsScalarTower 𝕜 A A
inst✝² : SMulCommClass 𝕜 A A
inst✝¹ : StarModule 𝕜 A
p : A → Prop
p₁ : Unitization 𝕜 A → Prop
hp₁ : ∀ {x : A}, p₁ ↑x ↔ p x
a : A
ha : p a
inst✝ : ContinuousFunctionalCalculus 𝕜 p₁
⊢ IsClosedEmbedding ⇑↑(Homeomorph.compStarAlgEquiv' 𝕜 𝕜 (Homeomorph.setCongr ⋯))

Tactic:
let e : C(σₙ 𝕜 a, 𝕜) ≃ₜ C(σ 𝕜 (a : A⁺¹), 𝕜) :=
  (Homeomorph.setCongr (quasispectrum_eq_spectrum_inr' 𝕜 𝕜 a)).arrowCongr (.refl _)

Result:
𝕜 : Type u_1
A : Type u_2
inst✝⁷ : RCLike 𝕜
inst✝⁶ : NonUnitalNormedRing A
inst✝⁵ : StarRing A
inst✝⁴ : NormedSpace 𝕜 A
inst✝³ : IsScalarTower 𝕜 A A
inst✝² : SMulCommClass 𝕜 A A
inst✝¹ : StarModule 𝕜 A
p : A → Prop
p₁ : Unitization 𝕜 A → Prop
hp₁ : ∀ {x : A}, p₁ ↑x ↔ p x
a : A
ha : p a
inst✝ : ContinuousFunctionalCalculus 𝕜 p₁
e : C(↑(σₙ 𝕜 a), 𝕜) ≃ₜ C(↑(σ 𝕜 ↑a), 𝕜) := (Homeomorph.setCongr ⋯).arrowCongr (Homeomorph.refl 𝕜)
⊢ IsClosedEmbedding ⇑↑(Homeomorph.compStarAlgEquiv' 𝕜 𝕜 (Homeomorph.setCongr ⋯))

Proof state:
𝕜 : Type u_1
A : Type u_2
inst✝⁷ : RCLike 𝕜
inst✝⁶ : NonUnitalNormedRing A
inst✝⁵ : StarRing A
inst✝⁴ : NormedSpace 𝕜 A
inst✝³ : IsScalarTower 𝕜 A A
inst✝² : SMulCommClass 𝕜 A A
inst✝¹ : StarModule 𝕜 A
p : A → Prop
p₁ : Unitization 𝕜 A → Prop
hp₁ : ∀ {x : A}, p₁ ↑x ↔ p x
a : A
ha : p a
inst✝ : ContinuousFunctionalCalculus 𝕜 p₁
e : C(↑(σₙ 𝕜 a), 𝕜) ≃ₜ C(↑(σ 𝕜 ↑a), 𝕜) := (Homeomorph.setCongr ⋯).arrowCongr (Homeomorph.refl 𝕜)
⊢ IsClosedEmbedding ⇑↑(Homeomorph.compStarAlgEquiv' 𝕜 𝕜 (Homeomorph.setCongr ⋯))

Tactic:
exact e.isClosedEmbedding

Result:
no goals