Results 11 to 20 of about 19,468 (288)
Approximation of Analytic Functions: A Method of Enhanced Convergence [PDF]
Mathematics of Computation, 1994 We deal with a method of enhanced convergence for the approximation of analytic functions. This method introduces conformal transformations in the approximation problems, in order to help extract the values of a given analytic function from its Taylor expansion around a point.
Bruno, Oscar P., Reitich, Fernando
core +6 more sources
Analytic approximation of matrix functions in $L^p$
Journal of Approximation Theory, 2008 We consider the problem of approximation of matrix functions of class $L^p$ on the unit circle by matrix functions analytic in the unit disk in the norm of $L^p$, $2\le ...
Laurent Baratchart +2 more
openaire +5 more sources
Joint discrete approximation of a pair of analytic functions by periodic zeta-functions
Mathematical Modelling and Analysis, 2020 In the paper, the problem of simultaneous approximation of a pair of analytic functions by a pair of discrete shifts of the periodic and periodic Hurwitz zeta-function is considered. The above shifts are defined by using the sequence of imaginary parts of
Aidas Balčiūnas +5 more
doaj +3 more sources
Nonlinear Analysis, 2020 In the paper, joint discrete universality theorems on the simultaneous approximation of a collection of analytic functions by a collection of discrete shifts of zeta-functions attached to normalized Hecke-eigen cusp forms are obtained.
Antanas Laurinčikas +2 more
doaj +3 more sources
About the rate of rational approximation of some analytic functions
Mathematical Modelling and Analysis, 1998 The article is devoted to results relating to the theory of rational approximation of an analytic function. Let ƒ be an analytic function on the disk {z : |z| < ñ), ñ > 1. The rate of decrease of the best approximations ñn of a function ƒ by the rational
A. YA. Radyno
doaj +3 more sources
On best rational approximation of analytic functions
Journal of Approximation Theory, 2005 The main result contained in this paper is described as follows. Let \(E\) be a compact set in the extended complex plane \(\overline{C}\), \(n\) be a nonnegative integer and \(f:E \to C\) be continuous. Let us consider the best rational approximation \(\rho_n(f,E)\) of \(f\) in the uniform metric \(\| \cdot - \cdot \| _E\) on \(E\) by the set \(R_n ...
Prokhorov, V.A.
openaire +3 more sources
Joint discrete approximation of analytic functions by shifts of Lerch zeta-functions
Mathematical Modelling and AnalysisThe Lerch zeta-function depends on two real parameters λ and and, for σ > 1, is defined by the Dirichlet series , and by analytic continuation elsewhere. In the paper, we consider the joint approximation of collections of analytic functions by discrete
Antanas Laurinčikas +2 more
doaj +3 more sources
Joint discrete approximation of analytic functions by Hurwitz zeta-functions
Mathematical Modelling and Analysis, 2022 Let H(D) be the space of analytic functions on the strip . In this paper, it is proved that there exists a closed non-empty set such that every collection of the functions is approximated by discrete shifts , of Hurwitz zeta-functions with arbitrary ...
Aidas Balčiūnas +4 more
doaj +1 more source
Joint universality of periodic zeta-functions with multiplicative coefficients. II
Nonlinear Analysis, 2021 In the paper, a joint discrete universality theorem for periodic zeta-functions with multiplicative coefficients on the approximation of analytic functions by shifts involving the sequence f kg of imaginary parts of nontrivial zeros of the Riemann zeta ...
Antanas Laurinčikas +2 more
doaj +1 more source
Some New Results on Bicomplex Bernstein Polynomials
Mathematics, 2021 The aim of this work is to consider bicomplex Bernstein polynomials attached to analytic functions on a compact C2-disk and to present some approximation properties extending known approximation results for the complex Bernstein polynomials. Furthermore,
Carlo Cattani +3 more
doaj +1 more source