Search results for "vep"
showing 10 items of 39 documents
Local spectral theory for Drazin invertible operators
2016
Abstract In this paper we investigate the transmission of some local spectral properties from a bounded linear operator R, as SVEP, Dunford property (C), and property (β), to its Drazin inverse S, when this does exist.
On the stability of the localized single-valued extension property under commuting perturbations
2013
This article concerns the permanence of the single-valued extension property at a point under suitable perturbations. While this property is, in general, not preserved under sums and products of commuting operators, we obtain positive results in the case of commuting perturbations that are quasi-nilpotent, algebraic, or Riesz operators.
Property (gR) and perturbations
2012
Property (gR) holds for a bounded linear operator T defined on a complex Banach space X, the isolated points of the spectrum of T which are eigenvalues of finite multiplicity are exactly those points c of the approximate point spectrum such cI -T is upper semi B-Browder. In this paper we consider the permanence of this property under nilpotent, perturbations commuting with T.
ACUITA’ VISIVA, PERFORMANCE DI LETTURA, QUALITA’ DELLA VITA E SENSIBILITA’ AL CONTRASTO SOGGETTIVA ED ELETTROFUNZIONALE IN PAZIENTI AFFETTI DA CATARA…
SINDROME DI APERT, SVILUPPO NEUROPSICOMOTORIO E FUNZIONE VISIVA: FATTORI DI RISCHIO PROGNOSTICO IN TRE PAZIENTI
2009
Premessa: La sindrome di Apert, è causata da mutazione (Pro253Arg e Ser253Trp) a livello dell’esone 8 del gene FGFR2 (10q26). Tra i fattori di rischio in termini di prognosi evolutiva si annoverano il tipo di mutazione (1), la presenza di anomalie dello sviluppo cerebrale, la prematurità, la sofferenza cerebrale perinatale, lo stato di ossigenazione, la strategia e i tempi di intervento neurochirurgico e correttivo. Obiettivi: Valutare in soggetti con S. di Apert la correlazione tra fattori di rischio e lo sviluppo neuropsicomotorio e neurosensoriale visivo. Metodologia:Tre soggetti con diversa combinazione dei fattori di rischio, sono stati valutati con potenziali evocati visivi da flash (…
Optical retarder system with programmable spectral retardance.
2014
An optical system that works as a retarder waveplate with programmable spectral retardance is proposed. The system is based on a pixelated liquid crystal on silicon (LCoS) spatial light modulator (SLM). The input light beam is spectrally dispersed and different spectral components are projected onto different pixels of the LCoS-SLM. A different retardance is then addressed for each pixel, adapted to the incoming wavelength. Light reflected from the SLM is then recombined by the same setup. In this way a programmable polarization spectrum can be encoded. We illustrate the broadband characterization that is required for proper use of the system. Then several examples are shown, including spec…
SVEP and local spectral radius formula for unbounded operators
2014
In this paper we study the localized single valued extension property for an unbounded operator T. Moreover, we provide sufficient conditions for which the formula of the local spectral radius holds for these operators.
On the effect of quarter-wave-plate errors in stress-holo-interferometry
1975
Weyl Type Theorems for Left and Right Polaroid Operators
2010
A bounded operator defined on a Banach space is said to be polaroid if every isolated point of the spectrum is a pole of the resolvent. In this paper we consider the two related notions of left and right polaroid, and explore them together with the condition of being a-polaroid. Moreover, the equivalences of Weyl type theorems and generalized Weyl type theorems are investigated for left and a-polaroid operators. As a consequence, we obtain a general framework which allows us to derive in a unified way many recent results, concerning Weyl type theorems (generalized or not) for important classes of operators.
Generalized Browder’s Theorem and SVEP
2007
A bounded operator \(T \in L(X), X\) a Banach space, is said to verify generalized Browder’s theorem if the set of all spectral points that do not belong to the B-Weyl’s spectrum coincides with the set of all poles of the resolvent of T, while T is said to verify generalized Weyl’s theorem if the set of all spectral points that do not belong to the B-Weyl spectrum coincides with the set of all isolated points of the spectrum which are eigenvalues. In this article we characterize the bounded linear operators T satisfying generalized Browder’s theorem, or generalized Weyl’s theorem, by means of localized SVEP, as well as by means of the quasi-nilpotent part H0(λI − T) as λ belongs to certain …