Module: Mathlib.Analysis.SpecialFunctions.ContinuousFunctionalCalculus.PosPart.Basic

Goal state before:
pp: case e'_6
A : Type u_1
inst✝¹¹ : NonUnitalRing A
inst✝¹⁰ : Module ℝ A
inst✝⁹ : SMulCommClass ℝ A A
inst✝⁸ : IsScalarTower ℝ A A
inst✝⁷ : StarRing A
inst✝⁶ : TopologicalSpace A
inst✝⁵ : NonUnitalContinuousFunctionalCalculus ℝ A IsSelfAdjoint
inst✝⁴ : PartialOrder A
inst✝³ : StarOrderedRing A
inst✝² : NonnegSpectrumClass ℝ A
inst✝¹ : IsSemitopologicalRing A
inst✝ : T2Space A
a b c : A
habc : a = b - c
hbc : b * c = 0
hb : 0 ≤ b
hc : 0 ≤ c
hb' : IsSelfAdjoint b
hc' : IsSelfAdjoint (-c)
ha : IsSelfAdjoint a
s : Set ℝ := σₙ ℝ a ∪ σₙ ℝ b ∪ σₙ ℝ (-c)
hs : CompactSpace ↑s
has : σₙ ℝ a ⊆ s
hbs : σₙ ℝ b ⊆ s
hcs : σₙ ℝ (-c) ⊆ s
this : Fact (0 ∈ s)
mul₁ : ∀ (f g : C(↑s, ℝ)₀), (cfcₙHomSuperset hb' hbs) f * (cfcₙHomSuperset hc' hcs) g = 0
mul₂ : ∀ (f g : C(↑s, ℝ)₀), (cfcₙHomSuperset hc' hcs) f * (cfcₙHomSuperset hb' hbs) g = 0
ψ : C(↑s, ℝ)₀ →⋆ₙₐ[ℝ] A :=
  let __src := ↑(cfcₙHomSuperset hb' hbs) + ↑(cfcₙHomSuperset hc' hcs);
  { toFun := ⇑(cfcₙHomSuperset hb' hbs) + ⇑(cfcₙHomSuperset hc' hcs), map_smul' := ⋯, map_zero' := ⋯, map_add' := ⋯,
    map_mul' := ⋯, map_star' := ⋯ }
f : C(↑s, ℝ)₀ := { toFun := fun x ↦ (↑x)⁺, continuous_toFun := ⋯, map_zero' := ⋯ }
key :
  cfcₙ
      (Function.extend Subtype.val ⇑(f.comp { toFun := Subtype.map id has, continuous_toFun := ⋯, map_zero' := ⋯ })
        fun x ↦ x⁺)
      a =
    cfcₙ
        (Function.extend Subtype.val ⇑(f.comp { toFun := Subtype.map id hbs, continuous_toFun := ⋯, map_zero' := ⋯ })
          fun x ↦ x⁺)
        b +
      cfcₙ
        (Function.extend Subtype.val ⇑(f.comp { toFun := Subtype.map id hcs, continuous_toFun := ⋯, map_zero' := ⋯ })
          fun x ↦ x⁺)
        (-c)
x : ℝ
hx : x ∈ σₙ ℝ (-c)
⊢ 0 ≤ -x

Tactic:
rw [Unitization.quasispectrum_eq_spectrum_inr ℝ (-c), Unitization.inr_neg,
          ← spectrum.neg_eq, Set.mem_neg, ← Unitization.quasispectrum_eq_spectrum_inr ℝ c]
          at hx

Goal state after:
case e'_6
A : Type u_1
inst✝¹¹ : NonUnitalRing A
inst✝¹⁰ : Module ℝ A
inst✝⁹ : SMulCommClass ℝ A A
inst✝⁸ : IsScalarTower ℝ A A
inst✝⁷ : StarRing A
inst✝⁶ : TopologicalSpace A
inst✝⁵ : NonUnitalContinuousFunctionalCalculus ℝ A IsSelfAdjoint
inst✝⁴ : PartialOrder A
inst✝³ : StarOrderedRing A
inst✝² : NonnegSpectrumClass ℝ A
inst✝¹ : IsSemitopologicalRing A
inst✝ : T2Space A
a b c : A
habc : a = b - c
hbc : b * c = 0
hb : 0 ≤ b
hc : 0 ≤ c
hb' : IsSelfAdjoint b
hc' : IsSelfAdjoint (-c)
ha : IsSelfAdjoint a
s : Set ℝ := σₙ ℝ a ∪ σₙ ℝ b ∪ σₙ ℝ (-c)
hs : CompactSpace ↑s
has : σₙ ℝ a ⊆ s
hbs : σₙ ℝ b ⊆ s
hcs : σₙ ℝ (-c) ⊆ s
this : Fact (0 ∈ s)
mul₁ : ∀ (f g : C(↑s, ℝ)₀), (cfcₙHomSuperset hb' hbs) f * (cfcₙHomSuperset hc' hcs) g = 0
mul₂ : ∀ (f g : C(↑s, ℝ)₀), (cfcₙHomSuperset hc' hcs) f * (cfcₙHomSuperset hb' hbs) g = 0
ψ : C(↑s, ℝ)₀ →⋆ₙₐ[ℝ] A :=
  let __src := ↑(cfcₙHomSuperset hb' hbs) + ↑(cfcₙHomSuperset hc' hcs);
  { toFun := ⇑(cfcₙHomSuperset hb' hbs) + ⇑(cfcₙHomSuperset hc' hcs), map_smul' := ⋯, map_zero' := ⋯, map_add' := ⋯,
    map_mul' := ⋯, map_star' := ⋯ }
f : C(↑s, ℝ)₀ := { toFun := fun x ↦ (↑x)⁺, continuous_toFun := ⋯, map_zero' := ⋯ }
key :
  cfcₙ
      (Function.extend Subtype.val ⇑(f.comp { toFun := Subtype.map id has, continuous_toFun := ⋯, map_zero' := ⋯ })
        fun x ↦ x⁺)
      a =
    cfcₙ
        (Function.extend Subtype.val ⇑(f.comp { toFun := Subtype.map id hbs, continuous_toFun := ⋯, map_zero' := ⋯ })
          fun x ↦ x⁺)
        b +
      cfcₙ
        (Function.extend Subtype.val ⇑(f.comp { toFun := Subtype.map id hcs, continuous_toFun := ⋯, map_zero' := ⋯ })
          fun x ↦ x⁺)
        (-c)
x : ℝ
hx : -x ∈ σₙ ℝ c
⊢ 0 ≤ -x