English

Diversity

Combinatorics 2018-11-06 v1 Discrete Mathematics

Abstract

Given a family F2[n]\mathcal F\subset 2^{[n]}, its diversity is the number of sets not containing an element with the highest degree. The concept of diversity has proven to be very useful in the context of kk-uniform intersecting families. In this paper, we study (different notions of) diversity in the context of other extremal set theory problems. One of the main results of the paper is a sharp stability result for cross-intersecting families in terms of diversity and, slightly more generally, sharp stability for the Kruskal--Katona theorem.

Keywords

Cite

@article{arxiv.1811.01111,
  title  = {Diversity},
  author = {Peter Frankl and Andrey Kupavskii},
  journal= {arXiv preprint arXiv:1811.01111},
  year   = {2018}
}
R2 v1 2026-06-23T05:02:46.681Z