English

Partitioning all $k$-subsets into $r$-wise intersecting families

Combinatorics 2021-09-27 v2 Discrete Mathematics

Abstract

Let r2r \geq 2, nn and kk be integers satisfying kr1rnk \leq \frac{r-1}{r}n. In the original arXiv version of this note we suggested a conjecture that the family of all kk-subsets of an nn-set cannot be partitioned into fewer than nrr1(k1)\lceil n-\frac{r}{r-1}(k-1) \rceil rr-wise intersecting families. We noted that if true this is tight for all values of the parameters, that the case r=2r=2 is Kneser's conjecture, proved by Lov\'asz, and observed that the assertion also holds provided rr is either a prime number or a power of 22. We have recently learned, however, that the assertion of the conjecture for all values of the parameters follows from a recent result of Azarpendar and Jafari \cite{AJ}.

Keywords

Cite

@article{arxiv.2107.12741,
  title  = {Partitioning all $k$-subsets into $r$-wise intersecting families},
  author = {Noga Alon},
  journal= {arXiv preprint arXiv:2107.12741},
  year   = {2021}
}
R2 v1 2026-06-24T04:33:33.687Z