Comparison of Norms |||f (A) - f(B) ||| and |||f (|A - B|) |||.
T. Ando (1988)
Mathematische Zeitschrift
D. Deng, X. T. Duong, A. Sikora, l. Yan (2008)
Revista Matemática Iberoamericana
Ivo Marek, Daniel B. Szyld (1990/1991)
Numerische Mathematik
Jean Roydor (2007)
Banach Center Publications
We describe the subspaces of (1 ≤ p ≠ 2 < ∞) which are the range of a completely contractive projection.
Ioana Ghenciu, Paul Lewis (2012)
Colloquium Mathematicae
A Banach space X has the Dunford-Pettis property (DPP) provided that every weakly compact operator T from X to any Banach space Y is completely continuous (or a Dunford-Pettis operator). It is known that X has the DPP if and only if every weakly null sequence in X is a Dunford-Pettis subset of X. In this paper we give equivalent characterizations of Banach spaces X such that every weakly Cauchy sequence in X is a limited subset of X. We prove that every operator T: X → c₀ is completely continuous...
Sameer Chavan, V. M. Sholapurkar (2015)
Studia Mathematica
Motivated by some structural properties of Drury-Arveson d-shift, we investigate a class of functions consisting of polynomials and completely monotone functions defined on the semi-group ℕ of non-negative integers, and its operator-theoretic counterpart which we refer to as the class of completely hypercontractive tuples of finite order. We obtain a Lévy-Khinchin type integral representation for the spherical generating tuples associated with such operator tuples and discuss its applications.
Yang, Mingze (1994)
International Journal of Mathematics and Mathematical Sciences
Marek Bożejko (1998)
Banach Center Publications
Emmanuel Fricain (2002)
Annales de l’institut Fourier
Soit une suite de Blaschke du disque unité et une fonction intérieure. On suppose que la suite de noyaux reproduisants est complète dans l’espace modèle , . On étudie, dans un premier temps, la stabilité de cette propriété de complétude, à la fois sous l’effet de perturbations des fréquences mais également sous l’effet de perturbations de la fonction . On retrouve ainsi un certain nombre de résultats classiques sur les systèmes d’exponentielles. Puis, si on suppose de plus que la suite ...
N.J. Nielsen, G.H. Olsen (1977)
Mathematica Scandinavica
Cao Jiang, Shi-An Han, Ze-Hua Zhou (2020)
Czechoslovak Mathematical Journal
This paper identifies a class of complex symmetric weighted composition operators on that includes both the unitary and the Hermitian weighted composition operators, as well as a class of normal weighted composition operators identified by Bourdon and Narayan. A characterization of algebraic weighted composition operators with degree no more than two is provided to illustrate that the weight function of a complex symmetric weighted composition operator is not necessarily linear fractional.
Xiao-He Hu (2022)
Czechoslovak Mathematical Journal
We give a concrete description of complex symmetric monomial Toeplitz operators on the weighted Bergman space , where denotes the unit ball or the unit polydisk. We provide a necessary condition for to be complex symmetric. When , we prove that is complex symmetric on if and only if and . Moreover, we completely characterize when monomial Toeplitz operators on are -symmetric with the symmetric unitary matrix .
Armin Rainer, Gerhard Schindl (2014)
Studia Mathematica
We characterize stability under composition of ultradifferentiable classes defined by weight sequences M, by weight functions ω, and, more generally, by weight matrices , and investigate continuity of composition (g,f) ↦ f ∘ g. In addition, we represent the Beurling space and the Roumieu space as intersection and union of spaces and for associated weight sequences, respectively.
Andreas Defant, Mieczysław Mastyło (2003)
Studia Mathematica
The Banach operator ideal of (q,2)-summing operators plays a fundamental role within the theory of s-number and eigenvalue distribution of Riesz operators in Banach spaces. A key result in this context is a composition formula for such operators due to H. König, J. R. Retherford and N. Tomczak-Jaegermann. Based on abstract interpolation theory, we prove a variant of this result for (E,2)-summing operators, E a symmetric Banach sequence space.
Jiang, Zhijie, Cao, Guangfu (2009)
Journal of Inequalities and Applications [electronic only]
Manhas, J.S. (2007)
International Journal of Mathematics and Mathematical Sciences
E. Diamantopoulos, Aristomenis Siskakis (2000)
Studia Mathematica
The Hilbert matrix acts on Hardy spaces by multiplication with Taylor coefficients. We find an upper bound for the norm of the induced operator.
Li, Haiying, Liu, Peide, Wang, Maofa (2007)
JIPAM. Journal of Inequalities in Pure & Applied Mathematics [electronic only]
Li, Haiying, Liu, Peide (2008)
Banach Journal of Mathematical Analysis [electronic only]
García, Domingo, Maestre, Manuel, Sevilla-Peris, Pablo (2004)
Annales Academiae Scientiarum Fennicae. Mathematica