On a problem of Henning and Yeo about the transversal number of uniform linear systems whose 2-packing number is fixed
Abstract
A linear system is a pair where is a family of subsets on a ground finite set such that , for every . If all elements of of a linear system , then the linear system is called -uniform linear system. The transversal number of a linear system , , is the minimum cardinality of a subset satisfying , for every . The 2-packing number of a linear system , , is the maximum cardinality of a subset such that, any three elements of don't have a common point (are triplewise disjoint), that is, if three elements are chosen in , then they are not incidents in a common point. For , let be an -uniform linear system. In "{\sc M. A. Henning and A. Yeo:} {\it Hypergraphs with large transversal number,} Discrete Math. {\bf 313} (2013), no. 8, 959--966." Henning and Yeo state the following question: Is it true that if is an -uniform linear system then holds for all ?. In this note, we give some results of -uniform linear systems, whose 2-packing number is fixed, satisfying the inequality.
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Cite
@article{arxiv.1710.02501,
title = {On a problem of Henning and Yeo about the transversal number of uniform linear systems whose 2-packing number is fixed},
author = {Carlos A. Alfaro and Adrián Vázquez-Ávila},
journal= {arXiv preprint arXiv:1710.02501},
year = {2020}
}