Restriction of the continuous functional calculus to a scalar subring #
The main declaration in this file is:
SpectrumRestricts.cfc
: builds a continuous functional calculus over a subring of scalars. This is use for automatically deriving the continuous functional calculi on selfadjoint or positive elements from the one for normal elements.
This will allow us to take an instance of the
ContinuousFunctionalCalculus ℂ IsStarNormal
and produce both of the instances
ContinuousFunctionalCalculus ℝ IsSelfAdjoint
and ContinuousFunctionalCalculus ℝ≥0 (0 ≤ ·)
simply by proving:
IsSelfAdjoint x ↔ IsStarNormal x ∧ SpectrumRestricts Complex.re x
,0 ≤ x ↔ IsSelfAdjoint x ∧ SpectrumRestricts Real.toNNReal x
.
The homeomorphism spectrum S a ≃ₜ spectrum R a
induced by SpectrumRestricts a f
.
Equations
- One or more equations did not get rendered due to their size.
Instances For
If the spectrum of an element restricts to a smaller scalar ring, then a continuous functional calculus over the larger scalar ring descends to the smaller one.
Equations
- One or more equations did not get rendered due to their size.
Instances For
Given a ContinuousFunctionalCalculus S q
. If we form the predicate p
for a : A
characterized by: q a
and the spectrum of a
restricts to the scalar subring R
via
f : C(S, R)
, then we can get a restricted functional calculus
ContinuousFunctionalCalculus R p
.
The homeomorphism quasispectrum S a ≃ₜ quasispectrum R a
induced by
QuasispectrumRestricts a f
.
Equations
- One or more equations did not get rendered due to their size.
Instances For
If the quasispectrum of an element restricts to a smaller scalar ring, then a non-unital continuous functional calculus over the larger scalar ring descends to the smaller one.
Equations
- One or more equations did not get rendered due to their size.
Instances For
Alias of QuasispectrumRestricts.isClosedEmbedding_nonUnitalStarAlgHom
.
Given a NonUnitalContinuousFunctionalCalculus S q
. If we form the predicate p
for a : A
characterized by: q a
and the quasispectrum of a
restricts to the scalar subring R
via
f : C(S, R)
, then we can get a restricted functional calculus
NonUnitalContinuousFunctionalCalculus R p
.