University of Lübeck

output

19992026

most citedranger: A Fast Implementation of Random Forests for High Dimensional Data in C++ and R

3.5k citations

researchers with a paper here

Counting papers with at most 25 authors, so collaboration author lists do not stand in for the people here.

collaborating institutions

Showing math.CAShow all

15 papers · 1 filter

math.CA2025

Edge detection with polynomial frames on the sphere

Frederic Schoppert

In a recent article, we have shown that a variety of localized polynomial frames, including isotropic as well as directional systems, are suitable for detecting jump discontinuitie…

math.CA2025★ 1 cited

Directional polynomial wavelets on spheres

Frederic Schoppert

In this article, we construct discrete tight frames for $L^{2} (S^{d - 1})$ , $d \geq 3$ , which consist of localized polynomial wavelets with adjustable degrees of directionality.…

math.CA2022★ 3 cited

Approximation on hexagonal domains by Taylor-Abel-Poisson means

Jürgen Prestin, Viktor Savchuk, Andrii Shidlich

Approximative properties of the Taylor-Abel-Poisson linear summation me\-thod of Fourier series are considered for functions of several variables, periodic with respect to the hexa…

math.CA2020★ 15 cited

Approximation by sampling-type operators in $L_{p}$ -spaces

Yurii Kolomoitsev, Maria Skopina

Approximation properties of the sampling-type quasi-projection operators $Q_{j} (f, φ, φ)$ for functions $f$ from anisotropic Besov spaces are studied. Error estimates in $L_…

math.CA2019★ 3 cited

Approximation theorems for multivariate Taylor-Abel-Poisson means

Jürgen Prestin, Viktor Savchuk, Andrii Shidlich

We obtain direct and inverse approximation theorems of functions of several variables by Taylor-Abel-Poisson means in the integral metrics. We also show that norms of multipliers i…

math.CA2018★ 37 cited

Approximation by multivariate Kantorovich-Kotelnikov operators

Yu. Kolomoitsev, M. Skopina

Approximation properties of multivariate Kantorovich-Kotelnikov type operators generated by different band-limited functions are studied. In particular, a wide class of functions w…

math.CA2018★ 4 cited

On weighted conditions for the absolute convergence of Fourier integrals

Yu. Kolomoitsev, E. Liflyand

In this paper we obtain new sufficient conditions for representation of a function as an absolutely convergent Fourier integral. Unlike those known earlier, these conditions are gi…

math.CA2018

Inequalities in approximation theory involving fractional smoothness in $L_{p}$ , $0 < p < 1$

Yurii Kolomoitsev, Tetiana Lomako

In the paper, we study inequalities for the best trigonometric approximations and fractional moduli of smoothness involving the Weyl and Liouville-Grünwald derivatives in $L_{p}$ , $0…

math.CA2018★ 9 cited

On the growth of Lebesgue constants for convex polyhedra

Yurii Kolomoitsev, Tetiana Lomako

In the paper, new estimates of the Lebesgue constant $L (W) = \frac{1}{( 2 π ) ^{d}} \int_{T^{d}} k \in W \cap Z^{d} \sum e^{i (k, x)} d x$ …

math.CA2017★ 13 cited

On moduli of smoothness and averaged differences of fractional order

Yurii Kolomoitsev

We consider two types of fractional integral moduli of smoothness, which are widely used in theory of functions and approximation theory. In particular, we obtain new equivalences…

math.CA2015

Recovery of periodicities hidden in heavy-tailed noise

Illya M. Karabash, Jürgen Prestin

We address a parametric joint detection-estimation problem for discrete signals of the form $x (t) = \sum_{n = 1}^{N} α_{n} e^{- i λ_{n} t} + ε_{t}$ , $t \in N$ , with an additive no…

math.CA2015★ 1 cited

Sharp estimates of approximation of periodic functions in Hölder spaces

Yurii Kolomoitsev, Jürgen Prestin

The main purpose of the paper is to study sharp estimates of approximation of periodic functions in the Hölder spaces $H_{p}^{r, α}$ for all $0 < p \leq \infty$ and $0 < α \leq r$ . By using mo…

math.CA2014

Two ideals connected with strong right upper porosity at a point

V. Bilet, O. Dovgoshey, J. Prestin

Let $S P$ be the set of upper strongly porous at $0$ subsets of $R^{+}$ and let $I^(S P)$ be the intersection of maximal ideals $I \subseteq S P$ . Some characteristic prop…

math.CA2012★ 11 cited

Periodic wavelet frames and time-frequency localization

Elena A. Lebedeva, Jürgen Prestin

A family of Parseval periodic wavelet frames is constructed. The family has optimal time-frequency localization (in the sense of the Breitenberger uncertainty constant) with respec…

math.CA2011

An orthogonal polynomial analogue of the Landau-Pollak-Slepian time-frequency analysis

Wolfgang Erb

The aim of this article is to present a time-frequency theory for orthogonal polynomials on the interval [-1,1] that runs parallel to the time-frequency analysis of bandlimited fun…