English

Graph-null sets

Combinatorics 2026-02-03 v1 Classical Analysis and ODEs

Abstract

We say that a plane set AA is {\it graph-null,} if there is a function g ⁣:[0,1]Rg\colon [0,1] \to \mathbb{R} such that λ2(A+graphg)=0\lambda_2 (A+{\rm graph}\, g)=0. A plane set AA has the {\it translational Kakeya property} if, for every translated copy AA' of AA and for every ϵ>0\epsilon >0, there is a finite sequence of vertical and horizontal translations bringing AA to AA' such that the area touched during the horizontal translations is less than ϵ\epsilon. These properties are equivalent if AA is compact. We show that the graph of every absolutely continuous function is graph-null. Also, the graph of a typical continuous function is graph-null. Therefore, there are nowhere differentiable continuous functions whose graphs are graph-null. Still, we show that there exists a continuous function whose graph is not graph-null.

Keywords

Cite

@article{arxiv.2602.01195,
  title  = {Graph-null sets},
  author = {M. Laczkovich and A. Máthé},
  journal= {arXiv preprint arXiv:2602.01195},
  year   = {2026}
}
R2 v1 2026-07-01T09:30:09.901Z