English

Strong Colouring of the Qualitative Independence Hypergraph $3\text{-}QI(11,2)$

Combinatorics 2026-07-21 v1

Abstract

We determine the strong independence number of the qualitative independence hypergraph, 3-QI(11,2)3\text{-}QI(11, 2), using a technique that involves considering its vertices as subsets of {1,2,,11}\{1,2, \ldots, 11\} and assessing them as intersecting set systems. This gives the maximum size of colour classes in any strong colouring and thus, a lower bound on the strong chromatic number of 3-QI(11,2)3\text{-}QI(11,2). We leverage this bound along with an upper bound of the strong chromatic number of 3-QI(10,2)3\text{-}QI(10,2), to consequently, establish that the covering array number of 3-QI(11,2)3\text{-}QI(11, 2), CAN(3-QI(11,2),2)=11CAN(3\text{-}QI(11,2),2) = 11 and give a sufficient condition for a hypergraph HH to have CAN(H,2)=11CAN(H, 2)=11.

Keywords

Cite

@article{arxiv.2607.18667,
  title  = {Strong Colouring of the Qualitative Independence Hypergraph $3\text{-}QI(11,2)$},
  author = {Raina Mary Thomas and Yasmeen Akhtar},
  journal= {arXiv preprint arXiv:2607.18667},
  year   = {2026}
}