t-Pancyclic Arcs in Tournaments

Document Type : Original paper

Authors

1 School of Mathematical Sciences, Shanxi University, 030006 Taiyuan, China

2 Lehrstuhl C fuer Mathematik, RWTH Aachen University, 52056 Aachen, Germany

Abstract

Let T be a non-trivial tournament. An arc is \emph{t-pancyclic} in T, if it is contained in a cycle of length for every t|V(T)|. Let pt(T) denote the number of t-pancyclic arcs in T and ht(T) the maximum number of t-pancyclic arcs contained in the same Hamiltonian cycle of T. Moon ( J. Combin. Inform. System Sci., 19 (1994), 207-214) showed that h3(T)3 for any non-trivial strong tournament T and characterized the tournaments with h3(T)=3. In this paper, we generalize Moon's theorem by showing that ht(T)t for every 3t|V(T)| and characterizing all tournaments which satisfy ht(T)=t. We also present all tournaments which fulfill pt(T)=t

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