4,237 research outputs found
Toeplitz Operators on Weighted Bergman Spaces
In this article we characterize the boundedness and compactness of a
Toeplitz-type operator on weighted Bergman spaces satisfying the so-called
Bekolle-Bonami condition in terms of the Berezin transform
Composition Operators on the Dirichlet Space and Related Problems
In this paper we investigate the following problem: when a bounded analytic
function on the unit disk , fixing 0, is such that is orthogonal in ?, and consider the
problem of characterizing the univalent, full self-maps of in
terms of the norm of the composition operator induced. The first problem is
analogous to a celebrated question asked by W. Rudin on the Hardy space setting
that was answered recently ([3] and [15]). The second problem is analogous to a
problem investigated by J. Shapiro in [14] about characterization of inner
functions in the setting of .Comment: 8 pages, 1 figure. See also
http://webdelprofesor.ula.ve/nucleotachira/gchacon or
http://webdelprofesor.ula.ve/humanidades/grchaco
Constructing three emotion knowledge tests from the invariant measurement approach
Background. Psychological constructionist models like the Conceptual Act Theory (CAT) postulate that complex states such as emotions are composed of basic psychological ingredients that are more clearly respected by the brain than basic emotions. The objective of this study was the construction and initial validation of Emotion Knowledge measures from the CAT frame by means of an invariant measurement approach, the Rasch Model (RM). Psychological distance theory was used to inform item generation. Methods. Three EK testsemotion vocabulary (EV), close emotional situations (CES) and far emotional situations (FES)were constructed and tested with the RM in a community sample of 100 females and 100 males (age range: 18-65), both separately and conjointly. Results. It was corroborated that data-RM fit was sufficient. Then, the effect of type of test and emotion on Rasch-modelled item difficulty was tested. Significant effects of emotion on EK item difficulty were found, but the only statistically significant difference was that between "happiness" and the remaining emotions; neither type of test, nor interaction effects on EK item difficulty were statistically significant. The testing of gender differences was carried out after corroborating that differential item functioning (DIF) would not be a plausible alternative hypothesis for the results. No statistically significant sex-related differences were found out in EV, CES, FES, or total EK. However, the sign of d indicate that female participants were consistently better than male ones, a result that will be of interest for future meta-analyses. Discussion. The three EK tests are ready to be used as components of a higher-level measurement process.Fil: Delgado, Ana R.. Universidad de Salamanca; EspañaFil: Prieto, Gerardo. Universidad de Salamanca; EspañaFil: Burin, Debora Ines. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Psicología; Argentin
Variable exponent Fock spaces
summary:We introduce variable exponent Fock spaces and study some of their basic properties such as boundedness of evaluation functionals, density of polynomials, boundedness of a Bergman-type projection and duality. We also prove that under the global log-Hölder condition, the variable exponent Fock spaces coincide with the classical ones
Unifying approach to the quantification of bipartite correlations by Bures distance
The notion of distance defined on the set of states of a composite quantum
system can be used to quantify total, quantum and classical correlations in a
unifying way. We provide new closed formulae for classical and total
correlations of two-qubit Bell-diagonal states by considering the Bures
distance. Complementing the known corresponding expressions for entanglement
and more general quantum correlations, we thus complete the quantitative
hierarchy of Bures correlations for Bell-diagonal states. We then explicitly
calculate Bures correlations for two relevant families of states: Werner states
and rank-2 Bell-diagonal states, highlighting the subadditivity which holds for
total correlations with respect to the sum of classical and quantum ones when
using Bures distance. Finally, we analyse a dynamical model of two independent
qubits locally exposed to non-dissipative decoherence channels, where both
quantum and classical correlations measured by Bures distance exhibit freezing
phenomena, in analogy with other known quantifiers of correlations.Comment: 18 pages, 4 figures; published versio
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