\((2,C)\)-ordered path designs \(P(\nu, 3,1)\)

Elizabeth J. Billington1, Gaetano Quattrocchit2
1Centre for Discrete Mathematics and Computing Department of Mathematics The University of Queensland Queensland 4072, Australia
2Department of Mathematics University of Catania viale A. Doria 6 95125 Catania, Italy

Abstract

Let \(C\) be the underlying graph of a configuration of \(l\) blocks in a path design of order \(v\) and block size \(3\), \((V, \mathcal{B})\). We say that \((V, \mathcal{B})\) is \((l,C)\)-ordered if it is possible to order its blocks in such a way that each set of \(l\) consecutive blocks has the same underlying graph \(C\). In this paper, we completely solve the problem of the existence of a \((2,C)\)-ordered path design \(P(v, 3, 1)\) for any configuration having two blocks.