Results 81 to 90 of about 8,503 (184)

Small triangles

Journal of the London Mathematical Society, Volume 113, Issue 3, March 2026.
Abstract Heilbronn's triangle problem is a classical question in discrete geometry. It asks to determine the smallest number Δ=Δ(N)$\Delta = \Delta (N)$ for which every collection in N$N$ points in the unit square spans a triangle with area at most Δ$\Delta$.
Dmitrii Zakharov
wiley   +1 more source

Discrete Subspace Multiwindow Gabor Frames and Their Duals

Abstract and Applied Analysis, 2013
This paper addresses discrete subspace multiwindow Gabor analysis. Such a scenario can model many practical signals and has potential applications in signal processing.
Yun-Zhang Li, Yan Zhang
doaj   +1 more source

Discrete analogues of second‐order Riesz transforms

Journal of the London Mathematical Society, Volume 113, Issue 3, March 2026.
Abstract Discrete analogues of classical operators in harmonic analysis have been widely studied, revealing deep connections with areas such as ergodic theory and analytic number theory. This line of research is commonly known as Discrete Analogues in Harmonic Analysis (DAHA).
Rodrigo Bañuelos, Daesung Kim
wiley   +1 more source

Pseudo- Riesz Bases

In~\cite{holub1994bases} Holub introduced the concept of near-Riesz bases, as frames that can be considered Riesz bases for computational purposes or that exhibit certain desirable properties of Riesz bases. In this paper, we introduce a generalization of near-Riesz bases that includes sequences which are not necessarily frames.
Biswas, Deborpita, Mitkovski, Mishko
openaire   +2 more sources

Sufficient conditions for functions to form Riesz bases in L_2 and applications to nonlinear boundary-value problems

Electronic Journal of Differential Equations, 2001
We find sufficient conditions for systems of functions to be Riesz bases in $L_2(0,1)$. Then we improve a theorem presented in [13] by showing that a ``standard'' system of solutions of a nonlinear boundary-value problem, normalized to 1, is a Riesz ...
Peter E. Zhidkov
doaj  

Analysis and construction of a family of refinable functions based on generalized Bernstein polynomials

Journal of Inequalities and Applications, 2016
In this paper, we construct a new family of refinable functions from generalized Bernstein polynomials, which include pseudo-splines of Type II. A comprehensive analysis of the refinable functions is carried out.
Ting Cheng, Xiaoyuan Yang
doaj   +1 more source

Potential trace inequalities via a Calderón‐type theorem

Journal of the London Mathematical Society, Volume 113, Issue 3, March 2026.
Abstract In this paper, we develop a general theoretical tool for the establishment of the boundedness of notoriously difficult operators (such as potentials) on certain specific types of rearrangement‐invariant function spaces from analogous properties of operators that are easier to handle (such as fractional maximal operators).
Zdeněk Mihula, Luboš Pick, Daniel Spector   +2 more
wiley   +1 more source

An Operator Based Approach to Irregular Frames of Translates

Mathematics, 2019
We consider translates of functions in L 2 ( R d ) along an irregular set of points, that is, { ϕ ( · − λ k ) } k ∈ Z —where ϕ is a bandlimited function.
Peter Balazs, Sigrid Heineken
doaj   +1 more source

Compressive Space-Time Galerkin Discretizations of Parabolic Partial Differential Equations [PDF]

, 2015
We study linear parabolic initial-value problems in a space-time variational formulation based on fractional calculus. This formulation uses "time derivatives of order one half" on the bi-infinite time axis.
Larsson, Stig, Schwab, Christoph
core   +1 more source