3 papers
math.FA2026
Duality for Delsarte's extremal problem on locally compact Abelian groups
Elena E. Berdysheva, Bálint Farkas, Marcell Gaál +2
The Delsarte extremal problem for positive definite functions, originally introduced by Delsarte in coding theory to bound the size of error-correcting codes, has since found appli…
math.CA2026
Duality for Delsarte's extremal problem on compact Gelfand pairs
Elena E. Berdysheva, Bálint Farkas, Marcell Gaál +2
We study Delsarte-type problems for positive definite functions on compact Gelfand pairs as infinite-dimensional linear programming problems. This setup includes, as a particular c…
math.CA2025
Densitometria I. Discrete groups
Szil\' ard Gy. R\' ev\' esz, Imre Z. Ruzsa
An upper mean here is a subadditive functional defined on bounded functions on a commutative group which has, beside some natural requirements, the property we call r…