PhyslibAlpha.AlgebraicFramework.HilbertSpace.Unbounded.Cayley.Certificate
The bounded-unitary spectral interface
The bounded spectral theorem itself does not need the Cayley support condition from `Cayley/Measure.lean`: that condition is only needed once a bounded unitary's spectral measure is going to be pulled back to the real line. This file records the general output any construction of a bounded normal/unitary spectral measure must supply (`BoundedNormalSpectralData`, `BoundedUnitarySpectralData`), independently of how that measure is actually built — kept general so an arbitrary bounded normal operator can consume the same interface, not only Cayley unitaries.
`BoundedUnitarySpectralData` additionally exposes the real spectral measure obtained by pulling its (Cayley-supported) complex measure back through `cayleyInverseMap`, together with the exact uniqueness statement: a real spectral measure is determined by its Cayley pushforward.
- `BoundedNormalSpectralData` : a spectral measure reconstructing a bounded normal operator `U` in the weak identity-integral sense, with an integral-determined extensionality principle. - `BoundedUnitarySpectralData` : the same, plus the support condition needed to invert the Cayley map, and the resulting `realSpectralMeasure`.
A. Bounded normal spectral data
B. Bounded unitary spectral data
7 declarations
for `BoundedNormalSpectralData`
Let be a bounded normal operator. Suppose and are two instances of bounded normal spectral data associated with . If their corresponding spectral measures are identical, then and are equal.
for bounded normal spectral data
Let be a bounded normal operator on a complex Hilbert space. Let and be two instances of bounded normal spectral data associated with . If for every measurable function that is bounded (i.e., there exists a constant such that for all ), the bounded spectral integrals are equal: (where and are the spectral measures associated with and respectively), then .
Extensionality of Bounded Unitary Spectral Data via Spectral Measure Equality
For any two sets of bounded unitary spectral data and associated with a bounded unitary operator , if their underlying spectral measures are equal, then the spectral data and are equal.
Equality of bounded spectral integrals implies for bounded unitary spectral data
Let be a bounded unitary operator on a complex Hilbert space. Let and be two sets of bounded unitary spectral data associated with . If for every measurable and bounded function , the bounded spectral integrals with respect to their corresponding spectral measures are equal, i.e., then .
The real spectral measure of on
For a given set of bounded unitary spectral data on a Hilbert space , this definition constructs the spectral measure on the real line by pulling back the complex spectral measure of through the inverse Cayley map. This resulting measure is an element of `WOTSpectralMeasure ℝ H`.
The Cayley map of 's real spectral measure equals its complex spectral measure
Let be a set of bounded unitary spectral data on a Hilbert space . Let be the spectral measure on the real line obtained by pulling back the complex spectral measure of through the inverse Cayley map. Then, the pushforward of under the Cayley map is equal to the original complex spectral measure .
Uniqueness of real spectral measure recovery from Cayley pushforward
Let be an instance of bounded unitary spectral data on a Hilbert space . For any spectral measure on the real line (of type `WOTSpectralMeasure ℝ H`), if the Cayley pushforward of is equal to the complex spectral measure associated with (i.e., ), then is equal to the canonical real spectral measure constructed from .
