Intersecting families of sets are typically trivial

Series
Graph Theory Seminar
Time
Tuesday, March 30, 2021 - 3:45pm for 1 hour (actually 50 minutes)
Location
https://us04web.zoom.us/j/77238664391. For password, please email Anton Bernshteyn (bahtoh ~at~ gatech.edu)
Speaker
Lina Li – University of Waterloo – lina.li@uwaterloo.cahttps://sites.google.com/view/linali/
Organizer
Anton Bernshteyn

A family of subsets of $[n]$ is intersecting if every pair of its members has a non-trivial intersection. Determining the structure of large intersecting families is a central problem in extremal combinatorics. Frankl-Kupavskii and Balogh-Das-Liu-Sharifzadeh-Tran independently showed that for $n \geq 2k + c\sqrt{k\ln k}$, almost all $k$-uniform intersecting families are stars. Significantly improving their results, we show that the same conclusion holds for $n \geq 2k + 100 \ln k$. Our proof uses the Sapozhenko’s graph container method and the Das-Tran removal lemma.

This is joint work with József Balogh, Ramon I. Garcia and Adam Zsolt Wagner.