English

Lipschitz one sets modulo sets of measure zero

Classical Analysis and ODEs 2019-12-23 v3

Abstract

We denote the local "little" and "big" Lipschitz functions of a function f:RRf: {{\mathbb R}}\to {{\mathbb R}} by lipf {\mathrm {lip}}f and Lipf {\mathrm {Lip}}f. In this paper we continue our research concerning the following question. Given a set ERE {\subset} {{\mathbb R}} is it possible to find a continuous function ff such that lipf=1E {\mathrm {lip}}f=\mathbf{1}_E or Lipf=1E {\mathrm {Lip}}f=\mathbf{1}_E? In giving some partial answers to this question uniform density type (UDT) and strong uniform density type (SUDT) sets play an important role. In this paper we show that modulo sets of zero Lebesgue measure any measurable set coincides with a Lip1{\mathrm {Lip}} 1 set. On the other hand, we prove that there exists a measurable SUDT set EE such that for any GδG_\delta set E~\widetilde{E} satisfying EΔE~=0|E\Delta\widetilde{E}|=0 the set E~\widetilde{E} does not have UDT. Combining these two results we obtain that there exists Lip1{\mathrm {Lip}} 1 sets not having UDT, that is, the converse of one of our earlier results does not hold.

Keywords

Cite

@article{arxiv.1907.00823,
  title  = {Lipschitz one sets modulo sets of measure zero},
  author = {Z. Buczolich and B. Hanson and B. Maga and G. Vértesy},
  journal= {arXiv preprint arXiv:1907.00823},
  year   = {2019}
}

Comments

This is the version accepted to appear in Mathematica Slovaca

R2 v1 2026-06-23T10:08:48.981Z