English

Equitable block colourings

Combinatorics 2014-06-23 v1

Abstract

Let Σ=(X,B)\Sigma=(X,\mathcal B) a 44-cycle system of order v=1+8kv=1+8k. A cc-colouring of type ss is a map ϕ ⁣:BC\phi\colon \mathcal B\rightarrow \mathcal C, with CC set of colours, such that exactly cc colours are used and for every vertex xx all the blocks containing xx are coloured exactly with ss colours. Let 4k=qs+r4k=qs+r, with q,r0q,r\ge 0. ϕ\phi is \emph{equitable} if for every vertex xx the set of the 4k4k blocks containing xx is parted in rr colour classes of cardinality q+1q+1 and srs-r colour classes of cardinality qq. In this paper we study colourings for which sks|k, giving a description of equitable block colourings for c{s,s+1,,2s2+s3}c\in \{s,s+1,\dots,\lfloor\tfrac{2s^2+s}{3}\rfloor \}.

Keywords

Cite

@article{arxiv.1406.5454,
  title  = {Equitable block colourings},
  author = {Paola Bonacini and Lucia Marino},
  journal= {arXiv preprint arXiv:1406.5454},
  year   = {2014}
}
R2 v1 2026-06-22T04:43:30.837Z