English

Number of $A+B\ne C$ solutions in abelian groups and application to counting independent sets in hypergraphs

Number Theory 2020-12-29 v1 Combinatorics

Abstract

The paper deals with a problem of Additive Combinatorics. Let G{\mathbf G} be a finite abelian group of order NN. We prove that the number of subset triples A,B,CGA,B,C\subset {\mathbf G} such that for any xAx\in A, yBy\in B and zCz\in C one has x+yzx+y\ne z equals 34N+N3N+1+O((3c)N) 3\cdot 4^N+N3^{N+1} + O((3-c_*)^N) for some absolute constant c>0c_*>0. This provides a tight estimate for the number of independent sets in a special 3-uniform linear hypergraph and gives a support for the natural conjecture concerning the maximal possible number of independent sets in such hypergraphs on nn vertices.

Keywords

Cite

@article{arxiv.2012.13433,
  title  = {Number of $A+B\ne C$ solutions in abelian groups and application to counting independent sets in hypergraphs},
  author = {Aliaksei Semchankau and Dmitry Shabanov and Ilya Shkredov},
  journal= {arXiv preprint arXiv:2012.13433},
  year   = {2020}
}

Comments

15 pages