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This article provides a power series summability based Korovkin type approximation theorem for any fuzzy sequence of positive linear operators. Using the notion of fuzzy modulus of smoothness, we also derive an associated approximation…

General Mathematics · Mathematics 2022-02-07 Behar Baxhaku , Purshottam Narain Agrawal , Rahul Shukla

Approximation theory has long been concerned with the development of positive linear operators that effectively approximate classes of functions. Among the most well-known results in this area are Korovkin-type approximation theorems, which…

Functional Analysis · Mathematics 2025-10-15 Dilek Söylemez , Mehmet Ünver

We prove the basic trigonometric Korovkin approximation theorem for fuzzy valued functions of two variables and verify the approximation by the help of fuzzy modulus of continuity. Also, we introduce double level Fourier series of fuzzy…

General Mathematics · Mathematics 2021-10-01 Enes Yavuz

This survey paper contains a detailed self-contained introduction to Korovkin-type theorems and to some of their applications concerning the approximation of continuous functions as well as of L^p-functions, by means of positive linear…

Classical Analysis and ODEs · Mathematics 2010-09-15 Francesco Altomare

This paper establishes an abstract Korovkin-type approximation theorem in general spaces, extending the framework of approximation theory to accommodate broader contexts. A critical result supporting this theorem is the proof that any…

Functional Analysis · Mathematics 2025-09-03 Dilek Söylemez , Mehmet Ünver

Our main aim is to investigate the approximation properties for the summation integral type operators in a statistical sense. In this regard, we prove the statistical convergence theorem using well known Korovkin theorem and the degree of…

Functional Analysis · Mathematics 2019-12-24 Rishikesh Yadav , Ramakanta Meher , Vishnu Narayan Mishra

We consider summability methods generated by the class GM(2b). We generalize some related results of P. Pych-Taberska [Studia Math. XCVI (1990), 91-103] on strong approximation of almost periodic functions by their Fourier series and S. M.…

Classical Analysis and ODEs · Mathematics 2012-04-16 Włodzimierz Łenski , Bogdan Szal

We present Korovkin approximation theorems that incorporate summability methods. These result allows us to obtain a unified treatment of several previous results, focusing on the underlying structure and the properties that a summability…

Functional Analysis · Mathematics 2023-07-07 M. del Carmen Listán-García , María Pilar Romero de la Rosa

In this paper, using the concept of $A$-statistical convergence which is a regular (non-matrix) summability method, we obtain a general Korovkin type approximation theorem which concerns the problem of approximating a function $f$ by means…

Classical Analysis and ODEs · Mathematics 2007-05-23 Esra Erkus , Oktay Duman

We introduce certain linear positive operators and study some approximation properties of these operators in the space of functions, continuous on a compact set, of two variables. We also find the order of this approximation by using…

Classical Analysis and ODEs · Mathematics 2007-09-24 Fatma Tasdelen , Ali Olgun , Gulen Bascanbaz-Tunca

In this paper, we have proved four theorems on the degree of approximation of continuous functions by matrix means of their Fourier series which is expressed in terms of the modulus of continuity and a non-negative mediate function.

Classical Analysis and ODEs · Mathematics 2023-06-22 Xhevat Z. Krasniqi

In this paper we deal with the convergence of sequences of positive linear maps to a (not assumed to be linear) isometry on spaces of continuous functions. We obtain generalizations of known Korovkin-type results and provide several…

Functional Analysis · Mathematics 2019-08-09 M. Hosseini , J. J. Font

This paper is aimed to prove a quantitative estimate (in terms of the modulus of continuity) for the convergence in the nonlinear version of Korovkin's theorem for sequences of weakly nonlinear and monotone operators defined on spaces of…

Functional Analysis · Mathematics 2024-04-18 Sorin G. Gal , Constantin P. Niculescu

In this paper, exact rate of approximation of functions by linear means of Fourier series and Fourier integrals and corresponding $K$-functionals are expressed via special moduli of smoothness. . Introduction is given in $\S 1$. In $\S2$…

Classical Analysis and ODEs · Mathematics 2016-06-27 R. M. Trigub

In the spaces $S^p$ of functions of several variables, $2\pi$-periodic in each variable, we study the approximative properties of operators $A^\vartriangle_{\varrho,r}$ and $P^\vartriangle_{\varrho,s}$, which generate two summation methods…

Classical Analysis and ODEs · Mathematics 2016-10-03 Viktor V. Savchuk , Andriy L. Shidlich

We give some Korovkin-type theorems on convergence and estimates of rates of approximations of nets of functions, satisfying suitable axioms, whose particular cases are filter/ideal convergence, almost convergence and triangular…

Functional Analysis · Mathematics 2021-01-15 Antonio Boccuto , Xenofon Dimitriou

In this paper, we give a degree of approximation of a function in the space $H_{p}^{(\omega, \omega)}$ by using the second type double delayed arithmetic means of its Fourier series. Such degree of approximation is expressed via two…

Classical Analysis and ODEs · Mathematics 2022-03-07 Xh. Z. Krasniqi , P. Kórus , B. Szal

A novel method of summation for power series is developed. The method is based on the self-similar approximation theory. The trick employed is in transforming, first, a series expansion into a product expansion and in applying the…

Statistical Mechanics · Physics 2009-11-10 V. I. Yukalov , S. Gluzman , D. Sornette

Fourier series multiscale method, a concise and efficient analytical approach for multiscale computation, will be developed out of this series of papers. The second paper is concerned with simultaneous approximation to functions and their…

Numerical Analysis · Mathematics 2022-08-09 Weiming Sun , Zimao Zhang

In this paper we study the exponential uniform strong summability of two-dimensional Vilenkin-Fourier series. In particular, it is proved that the two-dimensional Vilenkin-Fourier series of the continuous function $f$ is uniformly strong…

Analysis of PDEs · Mathematics 2016-09-16 Ushangi Goginava
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