English

Classification of maximum hittings by large families

Combinatorics 2019-10-10 v2

Abstract

For integers rr and nn, where nn is sufficiently large, and for every set X[n]X \subseteq [n] we determine the maximal left-compressed intersecting families A([n]r)\mathcal{A}\subseteq \binom{[n]}{r} which achieve maximum hitting with XX (i.e. have the most members which intersect XX). This answers a question of Barber, who extended previous results by Borg to characterise those sets XX for which maximum hitting is achieved by the star.

Keywords

Cite

@article{arxiv.1810.01707,
  title  = {Classification of maximum hittings by large families},
  author = {Candida Bowtell and Richard Mycroft},
  journal= {arXiv preprint arXiv:1810.01707},
  year   = {2019}
}

Comments

v2: minor corrections in response to reviewer comments. To appear in Graphs and Combinatorics