Results 41 to 50 of about 584,030 (179)

On Weighted Lp Integrability of Functions Defined by Trigonometric Series

Journal of Inequalities and Applications, 2010
We introduce a new class of sequences called GM¯θr and give a sufficient and necessary condition for weighted Lp integrability of trigonometric series with coefficients to belong to the above class.
Bogdan Szal
doaj   +1 more source

Approximation of classes B^ω_p,θ of periodic functions of several variables by polynomials with spectrum from cubic areas (in Ukrainian) [PDF]

Математичні Студії, 2011
We have obtained exact order estimates for error of approximation of classes B^ω_p,θ of periodic functions of several variables by trigonometric polynomials with spectrum from cubic areas.
S. A. Stasyuk
doaj  

Approximation by trigonometric polynomials in weighted rearrangement invariant spaces [PDF]

, 2009
We investigate the approximation properties of trigonometric polynomials and prove some direct and inverse theorems for polynomial approximation in weighted rearrangement invariant ...
Daniyal M. Israfilov, Ali Guven, Israfilov, Daniyal M., Guven, Ali   +3 more
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Computation of the Fourier transform for a continuous integrable function via NFFT

Frontiers in Applied Mathematics and Statistics
We investigate the approximation of continuous Fourier transforms by trigonometric sampling polynomials and their efficient evaluation by the non-equispaced fast Fourier transform (NFFT).
Daniel Potts, Manfred Tasche
doaj   +1 more source

Approximation by matrix transform in generalized grand Lebesgue spaces with variable exponent

Journal of Numerical Analysis and Approximation Theory, 2021
In this work the Lipschitz subclass of the generalized grand Lebesgue space with variable exponent is defined and the error of approximation by matrix transforms in this subclass is estimated.
Ahmet Testici, Daniyal Israfilov
doaj  

Accelerating convergence of trigonometric approximations [PDF]

Mathematics of Computation, 1970
Lanczos has recently developed a method for accelerating the convergence of trigonometric approximations for smooth, nonperiodic functions by modifying their boundary behavior. The method is reformulated here in terms of interpolation theory and is shown to be related to the theory of Lidstone interpolation.
Jones, William B., Hardy, G.
openaire   +2 more sources

Approximation of functions in Besov space by deferred Cesàro mean

Journal of Inequalities and Applications, 2016
In this paper we study the degree of approximation of functions (signals) in a Besov space by trigonometric polynomials using deferred Cesàro mean. We also deduce a few corollaries of our main result and compare them with the existing results.
Mradul Veer Singh, Madan Lal Mittal
doaj   +1 more source

Trigonometric approximation of functions f ( x , y ) $f(x,y)$ of generalized Lipschitz class by double Hausdorff matrix summability method

Advances in Difference Equations, 2020
In this paper, we establish a new estimate for the degree of approximation of functions f ( x , y ) $f(x,y)$ belonging to the generalized Lipschitz class L i p ( ( ξ 1 , ξ 2 ) ; r ) $Lip ((\xi _{1}, \xi _{2} );r )$ , r ≥ 1 $r \geq 1$ , by double ...
Abhishek Mishra, Vishnu Narayan Mishra, M. Mursaleen   +2 more
doaj   +1 more source

Refining trigonometric inequalities by using Padé approximant

Journal of Inequalities and Applications, 2018
A two-point Padé approximant method is presented for refining some remarkable trigonometric inequalities including the Jordan inequality, Kober inequality, Becker–Stark inequality, and Wu–Srivastava inequality. Simple proofs are provided.
Zhen Zhang, Huaqing Shan, Ligeng Chen
doaj   +1 more source

A note on some extremal problems for trigonometric polynomials [PDF]

n.a.
Dette, Holger, Melas, Viatcheslav B.
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