Results 81 to 90 of about 601 (93)

Convolution operators via orthogonal polynomials [PDF]

arXiv, 2020
In this paper we aim to generalize results obtained in the framework of fractional calculus by the way of reformulating them in terms of operator theory. In its own turn, the achieved generalization allows us to spread the obtained technique on practical problems that connected with various physical - chemical processes.
arxiv  

Asymptotic formulae for s-numbers of a Sobolev embedding and a Volterra type operator [PDF]

arXiv, 2015
Sharp upper and lower estimates are obtained of the approximation numbers of a Sobolev embedding and an integral operator of Volterra type. These lead to asymptotic formulae for the approximation numbers and certain other s-numbers.
arxiv  

Revisiting Operator $p$-Compact Mappings [PDF]

arXiv
We continue our study of the mapping ideal of operator $p$-compact maps, previously introduced by the authors. Our approach embraces a more geometric perspective, delving into the interplay between operator $p$-compact mappings and matrix sets, specifically we provide a quantitative notion of operator $p$-compactness for the latter.
arxiv  

Spectral equality for $C_0$ semigroups [PDF]

arXiv, 2016
In this paper, we give conditions for which the $C_0$ semigroups satisfies spectral equality for semiregular, essentially semiregular and semi-Fredholm spectrum. Also, we establish the spectral inclusion for B-Fredholm spectrum of a $C_0$ semigroups.
arxiv  

Characterization of nuclear pseudo-multipliers associated to the harmonic oscillator [PDF]

arXiv, 2018
In this paper we study pseudo-multipliers associated to the harmonic oscillator (also called Hermite multipliers) belonging to the ideal of $r$-nuclear operators on Lebesgue spaces.
arxiv  

Geometry of $\ell_p^n$-balls: Classical results and recent developments [PDF]

arXiv, 2018
This survey will appear as a chapter in the forthcoming "Proceedings of the HDP VIII Conference".
arxiv  

Transformations of sequence spaces by multipolinomials [PDF]

arXiv, 2018
In this paper we introduce a new approach to the concept of multipolynomials and generalize several results of the homogeneous polynomials and symmetric multilinear applications.
arxiv  

Injective polynomial ideals and the domination property [PDF]

arXiv, 2019
After sketching the basic theory of injective ideals of homogeneous polynomials, we characterize injective polynomial ideals by means of a domination property and applications of this characterization to some classical operator ideals and to composition polynomial ideals are provided.
arxiv  

Operator versions of Hölder inequality and Hilbert $C^*$-modules [PDF]

arXiv, 2019
Recently proved weighted Cauchy Scwarz inequality for Hilbert $C^*$-modules leads to many H\"older type inequalities for unitarily invariant norms on Hilbert space operators.
arxiv  

Spectral shift functions and Dirichlet-to-Neumann maps. [PDF]

Math Ann, 2018
Behrndt J, Gesztesy F, Nakamura S.
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