Results 21 to 30 of about 150 (46)

A uniform estimate of the relative projection constant

, 2017
The main goal of the paper is to provide a quantitative lower bound greater than $1$ for the relative projection constant $\lambda(Y, X)$, where $X$ is a subspace of $\ell_{2p}^m$ space and $Y \subset X$ is an arbitrary hyperplane.
Kobos, Tomasz
core   +1 more source

Multipliers for p-Bessel sequences in Banach spaces

, 2010
Multipliers have been recently introduced as operators for Bessel sequences and frames in Hilbert spaces. These operators are defined by a fixed multiplication pattern (the symbol) which is inserted between the analysis and synthesis operators.
A. Aldroubi, A. Aldroubi, A. Pietsch, A.F. Ruston, Asghar Rahimi, D. Wang, G. Matz, G. Matz, H. Rauhut, K. Gröchenig, M. Dörfler, M. Fornasier, M. Kowalski, M.R. Abodllahpour, O. Christensen, P. Balazs, P. Balazs, P. Balazs, P. Balazs, P. Balazs, P.G. Casazza, Peter Balazs, R. Schatten, R.M. Young   +23 more
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Lower bounds for the approximation with variation-diminishing splines [PDF]

We prove lower bounds for the approximation error of the variation-diminishing Schoenberg operator on the interval [0, 1] in terms of classical moduli of smoothness depending on the degree of the spline basis.
B. Forster, Badea, Beutel, Curry, de Boor, de Boor, de Boor, Gantmacher, Gavrea, Gershgorin, J. Nagler, Lyche, Marsden, Nürnberger, P. Cerejeiras, Pinkus, Rudin, Scherer, Schoenberg, Schoenberg, Schumaker, Timan, Zygmund   +22 more
core   +1 more source

Redundancy of Fusion frames in Hilbert Spaces

, 2015
Upon improving and extending the concept of redundancy of frames, we introduce the notion of redundancy of fusion frames, which is concerned with the properties of lower and upper redundancies. These properties are achieved by considering the minimum and
Daraby, Bayaz, Rahimi, Asghar, Zandi, Golaleh   +2 more
core   +1 more source

A coordinate free characterization of certain quasidiagonal operators [PDF]

, 2014
We obtain (i) a new, coordinate free, characterization of quasidiagonal operators with essential spectra contained in the unit circle by adapting the proof of a classical result in the theory of Banach spaces, (ii) an affirmative answer to some questions
Boedihardjo, March T.
core  

Full operators and algebras generated by invertible operators

, 2009
In the present work we characterized full operators and we showed some properties that have nonfull injectives operators. With the results developed for full operators, we affirmatively respond two questions formulated by Bravo and Feintuch on when the ...
R, Wilson R. Pacheco
core   +1 more source

Pad\'{e}-type approximations to the resolvent of fractional powers of operators

, 2019
We study a reliable pole selection for the rational approximation of the resolvent of fractional powers of operators in both the finite and infinite dimensional setting. The analysis exploits the representation in terms of hypergeometric functions of the
Aceto, Lidia, Novati, Paolo
core  

Approximation of Entropy Numbers

, 2017
The purpose of this article is to develop a technique to estimate certain bounds for entropy numbers of diagonal operator on spaces of p-summable sequences for finite p greater than 1.
Deepesh, K. P., Kumar, V. B. Kiran
core  

Endomorphisms of B(H)

, 1994
The unital endomorphisms of B(H) of (Powers) index n are classified by certain U(n)-orbits in the set of non-degenerate representations of the Cuntz algebra O_n on H.
Bratteli, Ola, Jorgensen, Palle, Price, Geoff   +2 more
core  

Review: A C*-algebra approach to complex symmetric operators [PDF]

, 2016
Garcia, Stephan Ramon
core   +1 more source