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In this paper asymptotic formulas are given for the Lebesgue constants generated by three special approximation processes related to the $\ell_1$-partial sums of Fourier series. In particular, we consider the Lagrange interpolation…

Classical Analysis and ODEs · Mathematics 2020-09-16 Yurii Kolomoitsev , Tetiana Lomako

We determine upper asymptotic estimates of Kolmogorov and linear $n$-widths of unit balls in Sobolev and Besov norms in $L_{p}$-spaces on smooth compact Riemannian manifolds. For compact homogeneous manifolds, we establish estimates which…

Functional Analysis · Mathematics 2015-02-13 Daryl Geller , Isaac Pesenson

We give a partial negative answer to a question left open in a previous work by Brasco and the first and third-named authors concerning the sharp constant in the fractional Hardy inequality on convex sets. Our approach has a geometrical…

Analysis of PDEs · Mathematics 2025-09-30 Francesca Bianchi , Giorgio Stefani , Anna Chiara Zagati

We establish sharp estimates for the convergence rate of the Kranosel'ski\v{\i}-Mann fixed point iteration in general normed spaces, and we use them to show that the asymptotic regularity bound recently proved in [11] (Israel Journal of…

Optimization and Control · Mathematics 2017-01-31 Mario Bravo , Roberto Cominetti

Markov's inequality for algebraic polynomials on $\left[-1,1\right]$ goes back to more than a century and it is widely used in approximation theory. Its asymptotically sharp form for unions of finitely many intervals has been found only in…

Complex Variables · Mathematics 2015-09-25 Sergei Kalmykov , Bela Nagy , Vilmos Totik

The Generalised Baker--Schmidt Problem (1970) concerns the $f$-dimensional Hausdorff measure of the set of $\psi$-approximable points on a nondegenerate manifold. There are two variants of this problem, concerning simultaneous and dual…

Number Theory · Mathematics 2021-06-25 Mumtaz Hussain , Johannes Schleischitz , David Simmons

The Generalised Baker-Schmidt Problem (1970) concerns the Hausdorff measure of the set of $\psi$-approximable points on a nondegenerate manifold. Beresnevich-Dickinson-Velani (in 2006, for the homogeneous setting) and…

Number Theory · Mathematics 2026-05-08 Mumtaz Hussain , Johannes Schleischitz , Benjamin Ward

We investigate projection constants for spaces of bihomogeneous harmonic and bihomogeneous polynomials on the unit sphere in finite-dimensional complex Hilbert spaces. Using averaging techniques, we demonstrate that the minimal norm…

Functional Analysis · Mathematics 2026-02-20 Andreas Defant , Daniel Galicer , Martín Mansilla , Mieczysław Mastyło , Santiago Muro

We study the computation of local approximations of invariant manifolds of parabolic fixed points and parabolic periodic orbits of periodic vector fields. If the dimension of these manifolds is two or greater, in general, it is not possible…

Dynamical Systems · Mathematics 2016-03-09 Inmaculada Baldomá , Ernest Fontich , Pau Martín

Linear statistics of random zero sets are integrals of smooth differential forms over the zero set and as such are smooth analogues of the volume of the random zero set inside a fixed domain. We derive an asymptotic expansion for the…

Complex Variables · Mathematics 2020-01-17 Bernard Shiffman

We introduce the notions of strong asymptotic uniform smoothness and convexity. We show that the injective tensor product of strongly asymptotically uniformly smooth spaces is asymptotically uniformly smooth. This applies in particular to…

Functional Analysis · Mathematics 2017-05-08 Luis García-Lirola , Matías Raja

This paper continues our work [19] on sharp Alexandrov estimates. We obtain a sharp global uniform distance estimate from a convex function to the class of unimodular convex quadratic polynomials in terms of the total variation of its…

Analysis of PDEs · Mathematics 2026-02-09 Tianling Jin , Xushan Tu , Jingang Xiong

We work in a discrete model of the nonlinear Fourier transform (following the terminology of Tao and Thiele), which appears in the study of orthogonal polynomials on the unit circle. The corresponding nonlinear variant of the…

Classical Analysis and ODEs · Mathematics 2023-08-22 Vjekoslav Kovač , Diogo Oliveira e Silva , Jelena Rupčić

Using a differential equation approach asymptotic expansions are rigorously obtained for Lommel, Weber, Anger-Weber and Struve functions, as well as Neumann polynomials, each of which is a solution of an inhomogeneous Bessel equation. The…

Classical Analysis and ODEs · Mathematics 2021-04-06 T. M. Dunster

In this paper, the asymptotic theory presented in (Caponera et al., 2022) for spline-type anysotropic covariance estimator on the 2-dimensional sphere is generalized to the case of connected and compact two-point homogeneous spaces.

Statistics Theory · Mathematics 2025-07-08 Alessia Caponera

We obtain an equivariant index theorem, or Lefschetz fixed-point formula, for isometries from complete Riemannian manifolds to themselves. The fixed-point set of such an isometry may be noncompact. We build on techniques developed by Roe.…

Differential Geometry · Mathematics 2024-01-10 Peter Hochs

We consider a singularly perturbed second order elliptic system in the whole space. The coefficients of the systems fast oscillate and depend both of slow and fast variables. We obtain the homogenized operator and in the uniform norm sense…

Mathematical Physics · Physics 2007-05-23 Denis Borisov

Recently we found necessary and sufficient conditions for the convergence at a preassigned point of the spherical partial sums of the Fourier integral in a class of piecewise smooth functions in Euclidean space. These yield elementary…

Classical Analysis and ODEs · Mathematics 2016-09-06 Mark A. Pinsky

In this paper we address the problem of estimating the operator norm of the embeddings between multidimensional weighted Paley-Wiener spaces. These can be equivalently thought as Fourier uncertainty principles for bandlimited functions. By…

We establish new sharp asymmetric Poincare inequalities in one-dimension with the computation of optimal constants and characterization of extremizers. Using the one-dimensional theory we develop a comprehensive study on fundamental…

Optimization and Control · Mathematics 2025-02-03 Julian Haddad , Raul Fernandes Horta , Marcos Montenegro
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