Don'at Nagy

activity

20162020

collaborators

6 papers

math.GN2020

Games characterizing limsup functions and Baire class 1 functions

Márton Elekes, János Flesch, Viktor Kiss +3

We consider a real-valued function $f$ defined on the set of infinite branches $X$ of a countably branching pruned tree $T$ . The function $f$ is said to be a \textit{limsup functio…

math.CA2020

Compact sets with large projections and nowhere dense sumset

Richárd Balka, Márton Elekes, Viktor Kiss +2

We answer a question of Banakh, Jabłońska and Jabłoński by showing that for $d \geq 2$ there exists a compact set $K \subseteq R^{d}$ such that the projection of $K$ onto each…

math.CA2019

Substituting the typical compact sets into a power series

Donát Nagy

The Minkowski sum and Minkowski product can be considered as the addition and multiplication of subsets of $R$ . If we consider a compact subset $K \subseteq [0, 1]$ and a pow…

math.LO2018

A Haar meager set that is not strongly Haar meager

Márton Elekes, Donát Nagy, Márk Poór +1

Following Darji, we say that a Borel subset $B$ of an abelian Polish group $G$ is Haar meager if there is a compact metric space $K$ and a continuous function $f : K \to G$ such th…

math.LO2016

Low complexity Haar null sets without G_δ hulls in Z^ω

Donát Nagy

We show that for every $2 \leq ξ < ω_{1}$ there exists a Haar null set in $Z^{ω}$ that is the difference of two $Π_{ξ}^{0}$ sets but not contained in any $Π_{ξ}^{0}$ Haar nu…

math.LO2016

Haar null and Haar meager sets: a survey and new results

Márton Elekes, Donát Nagy

We survey results about Haar null subsets of (not necessarily locally compact) Polish groups. The aim of this paper is to collect the fundamental properties of the various possible…