Hypergraphs of bounded disjointness

TL;DR

This paper proves a conjecture about the maximum size of certain hypergraphs with bounded disjointness, identifying extremal configurations and advancing understanding of hypergraph intersection properties.

Contribution

It proves a strengthened version of a conjecture on the maximum edges in s-almost intersecting hypergraphs and characterizes extremal graphs.

Findings

Confirmed the conjecture for all relevant parameters.

Identified extremal hypergraph structures.

Provided related results and conjectures.

Abstract

A $k$-uniform hypergraph is $s$-almost intersecting if every edge is disjoint from exactly $s$ other edges. Gerbner, Lemons, Palmer, Patk\'os and Sz\'ecsi conjectured that for every $k$, and $s>s_0(k)$, every $k$-uniform $s$-almost intersecting hypergraph has at most $(s+1)\binom{2k-2}{k-1}$ edges. We prove a strengthened version of this conjecture and determine the extremal graphs. We also give some related results and conjectures.