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Using techniques from semidefinite programming, we study the problem of finding a closest quantum channel to the projection onto a matricial subsystem. We derive two invariants of matricial subsystems which are related to the quantum…

Quantum Physics · Physics 2023-02-28 Roy Araiza , Colton Griffin , Aneesh Khilnani , Thomas Sinclair

In this paper we introduce the Stancu type generalization of the q-Bernstein-Schurer-Kantorovich operators and examine their approximation properties. We investigate the convergence of our operators with the help of the Korovkin's…

Classical Analysis and ODEs · Mathematics 2016-02-23 M. Mursaleen , Taqseer Khan

In this paper, we give some definitions on quasi-convex functions and we prove inequalities contain J-quasi-convex and W-quasi-convex functions. We give also some inclusions.

Classical Analysis and ODEs · Mathematics 2010-12-17 M. Emin Ozdemir , Ahmet Ocak Akdemir , Cetin Yildiz

The variation of spectral subspaces for linear self-adjoint operators under an additive bounded perturbation is considered. The objective is to estimate the norm of the difference of two spectral projections associated with isolated parts…

Spectral Theory · Mathematics 2022-02-02 Albrecht Seelmann

In the present paper, we introduce a Choldowsky type generalization of the q Favard-Szasz operators and obtain weighted statistical approximation properties of these operators. We also establish the rates of statistical convergence by means…

Classical Analysis and ODEs · Mathematics 2015-05-27 Ali Karaisa

We show that any Lipschitz projection-valued function p on a connected closed Riemannian manifold can be approximated uniformly by smooth projection-valued functions q with Lipschitz constant close to that of p. This answers a question of…

Operator Algebras · Mathematics 2019-08-15 Hanfeng Li

his paper deals with approximating properties of the newly defined $q$-generalization of the Sz\'{a}sz operators in the case $q>1$. Quantitative estimates of the convergence in the polynomial weighted spaces and the Voronovskaja's theorem…

Functional Analysis · Mathematics 2010-05-24 Nazim I. Mahmudov

The natural kinship between classical theories of interpolation and approximation is well explored. In contrast to this, the interrelation between interpolation and approximation is subtle and this duality is relatively obscure in the…

Dynamical Systems · Mathematics 2021-04-08 K. K. Pandey , P. Viswanathan

An important problem in applications of quasiconformal analysis and in its numerical aspect is to establish algorithms for explicit or approximate determination of the basic quasiinvariant curvelinear and analytic functionals intrinsically…

Complex Variables · Mathematics 2023-02-01 Samuel L. Krushkal

Let $(A_1,\cdots,A_n)$ and $(B_1,\cdots,B_n)$ be $n$-tuples of commuting self-adjoint operators on Hilbert space. For functions $f$ on $\R^n$ satisfying certain conditions, we obtain sharp estimates of the operator norms (or norms in…

Functional Analysis · Mathematics 2013-08-26 Fyodor Nazarov , Vladimir Peller

Given an operator ideal I, a Banach space E has the I-approximation property if operators on E can be uniformly approximated on compact subsets of E by operators belonging to I. In this paper the I- approximation property is studied in…

Functional Analysis · Mathematics 2010-09-16 Sonia Berrios , Geraldo Botelho

Let $\Omega\subset \mathbb{C}^n$ be a smooth bounded pseudoconvex domain and $A^2 (\Omega)$ denote its Bergman space. Let $P:L^2(\Omega)\longrightarrow A^2(\Omega)$ be the Bergman projection. For a measurable $\varphi:\Omega\longrightarrow…

Complex Variables · Mathematics 2021-05-25 Zeljko Cuckovic

In this paper, we introduce a Kantorovich type generalization of q-Bernstein-Stancu operators. We study the convergence of the introduced operators and also obtain the rate of convergence by these operators in terms of the modulus of…

Classical Analysis and ODEs · Mathematics 2015-05-27 M. Mursaleen , Khursheed J. Ansari , Asif Khan

Averaging certain class of quasiperiodic monotone operators can be simplified to the periodic homogenization setting by mapping the original quasiperiodic structure onto a periodic structure in a higher dimensional space using cut-and…

Analysis of PDEs · Mathematics 2023-06-21 Niklas Wellander , Sebastien Guenneau , Elena Cherkaev

Consider additive functionals of a Markov chain $W_k$, with stationary (marginal) distribution and transition function denoted by $\pi$ and $Q$, say $S_n=g(W_1)+...+g(W_n)$, where $g$ is square integrable and has mean 0 with respect to…

Probability · Mathematics 2008-11-14 Ou Zhao , Michael Woodroofe

In this paper we characterize quasi-contraction, stable and convergent weighted conditional type (WCT) operators on $L^p(\mu)$. Indeed we provide equivalent conditions for quasi-contraction WCT operators. Also, we prove that convergence,…

Functional Analysis · Mathematics 2024-06-13 Y. Estaremi , Z. Huang

We prove that the composition of a quasi-nearly subharmonic function and a quasiregular mappings of bounded multiplicity is quasi-nearly subharmonic. Also, we prove that if $u\circ f$ is quasi-nearly subharmonic for all quasi-nearly…

Functional Analysis · Mathematics 2011-03-09 Pekka Koskela , Vesna Manojlović

We obtain sharp estimates for the quasi norm of the maximal function of f when it satisfies certain conditions.

Functional Analysis · Mathematics 2010-01-28 Eleftherios N. Nikolidakis

It is known that the Bergman projection operator maps the space of essentially bounded functions in the unit ball in the d-dimensional complex vector space onto the Bloch space of the unit ball. This paper deals with the various semi-norms…

Complex Variables · Mathematics 2015-04-07 Marijan Markovic

Recent works have suggested that nonlinear (quadratic) effects in black hole perturbation theory may be important for describing a black hole ringdown. We show that the technique of uniform approximations can be used to accurately compute…

High Energy Physics - Theory · Physics 2023-12-12 Bruno Bucciotti , Adrien Kuntz , Francesco Serra , Enrico Trincherini