Intertwining the continuous functional calculus #
A real-linear operator intertwining two self-adjoint operators intertwines their continuous functional calculi (Weierstrass approximation).
T = |P − Q| = (R(2−R))^{1/2} and A = P − Q #
T := (R(2−R))^{1/2} (RvD's T, the modulus of P − Q).
Equations
Instances For
T² = R(2−R) (RvD Prop. 2.2(2)).
A := P − Q (conjugate-linear).
Equations
Instances For
A² = R(2−R) (RvD Prop. 2.2(2)).
A R = (2 − R) A (RvD Prop. 2.2(5) via the polar decomposition).
A T = T A (RvD Prop. 2.2(4)).
The antiunitary J: J (T x) = A x #
The range of T as a (dense) subspace.
Equations
Instances For
A preimage under T.
Equations
Instances For
J₀ : T x ↦ A x on the range of T, conjugate-linear and isometric.
Equations
- One or more equations did not get rendered due to their size.
Instances For
The antiunitary J, the continuous extension of T x ↦ A x (RvD §2, the partial isometry of
the polar decomposition P − Q = JT).
Equations
Instances For
Two continuous maps agreeing on the range of T agree everywhere.
T J = A (J commutes with T, RvD Prop. 2.2(4)).
Real symmetry Re⟪Jξ, η⟫ = Re⟪ξ, Jη⟫.
⟪Jξ, η⟫ = ⟪Jη, ξ⟫ (RvD Prop. 3.1).
J² = 1 (RvD Prop. 2.2(3)).
J R = (2 − R) J (RvD Prop. 2.2(5)).
J and the functional calculus of R #
J R = (2 − R) J transports the spectral data of R under λ ↦ 2 − λ: J g(R) = g(2 − R) J
for every bounded Borel g.
J as a real-linear operator.
Equations
- CommutingRepetition.VN.Modular.JmR M Ω = { toFun := ⇑(CommutingRepetition.VN.Modular.Jm M Ω), map_add' := ⋯, map_smul' := ⋯ }.mkContinuous ‖CommutingRepetition.VN.Modular.Jm M Ω‖ ⋯
Instances For
J f(R) = f(2 − R) J = (f ∘ (2 − ·))(R) J for continuous f.
The spectral measure of R at J ξ is the push-forward of the one at ξ under λ ↦ 2 − λ.
Conjugation G ↦ J G J by the antiunitary J, a (complex-linear) operator.
Equations
Instances For
J g(R) = (g ∘ (2 − ·))(R) J for bounded Borel g.
J Δ^{it} = Δ^{it} J (RvD Prop. 3.3).
Δ^{it} preserves 𝒦 (RvD Prop. 3.3): P = (R + A)/2 commutes with Δ^{it}.
The bounded identities T J (x Ω) = (2 − R)(x* Ω), T J (x' Ω) = R (x'* Ω) (RvD Lemma 4.5) #
For self-adjoint a' ∈ M', Q (a' Ω) = 0: a' Ω ⊥ i𝒦.
For self-adjoint a ∈ M, T J (a Ω) = (2 − R)(a Ω).
For self-adjoint a' ∈ M', A (a' Ω) = R (a' Ω).
Conjugate-linearity of A in the form used for the decomposition x = a + i b.
RvD Lemma 4.5 (first identity): T J (x Ω) = (2 − R)(x* Ω) for x ∈ M.
RvD Lemma 4.5 (second identity): T J (x' Ω) = R (x'* Ω) for x' ∈ M'.