English

A convex set with a rich difference

Combinatorics 2022-08-19 v2

Abstract

We construct a convex set AA with cardinality 2n2n and with the property that an element of the difference set AAA-A can be represented in nn different ways. We also show that this construction is optimal by proving that for any convex set AA, the maximum possible number of representations an element of AAA-A can have is A/2\lfloor |A|/2 \rfloor .

Keywords

Cite

@article{arxiv.2208.03258,
  title  = {A convex set with a rich difference},
  author = {Oliver Roche-Newton and Audie Warren},
  journal= {arXiv preprint arXiv:2208.03258},
  year   = {2022}
}

Comments

This version has been edited to include a reference to a paper of Schoen, which we were not previously aware of. The paper of Schoen proves a similar result, with a worse multiplicative constant

R2 v1 2026-06-25T01:31:03.239Z