English

Spectral Tur\'an Type Problems on Cancellative Hypergraphs

Combinatorics 2022-08-02 v2

Abstract

Let GG be a cancellative 33-uniform hypergraph in which the symmetric difference of any two edges is not contained in a third one. Equivalently, a 33-uniform hypergraph GG is cancellative if and only if GG is {F4,F5}\{F_4, F_5\}-free, where F4={abc,abd,bcd}F_4 = \{abc, abd, bcd\} and F5={abc,abd,cde}F_5 = \{abc, abd, cde\}. A classical result in extremal combinatorics stated that the maximum size of a cancellative hypergraph is achieved by the balanced complete tripartite 33-uniform hypergraph, which was firstly proved by Bollob\'as and later by Keevash and Mubayi. In this paper, we consider spectral extremal problems for cancellative hypergraphs. More precisely, we determine the maximum pp-spectral radius of cancellative 33-uniform hypergraphs, and characterize the extremal hypergraph. As a by-product, we give an alternative proof of Bollob\'as' result from spectral viewpoint.

Keywords

Cite

@article{arxiv.2207.03271,
  title  = {Spectral Tur\'an Type Problems on Cancellative Hypergraphs},
  author = {Zhenyu Ni and Lele Liu and Liying Kang},
  journal= {arXiv preprint arXiv:2207.03271},
  year   = {2022}
}

Comments

Fix mistakes and add a result on the Lagrangian of cancellative hypergraphs

R2 v1 2026-06-24T12:17:12.103Z