Cycles of given length in oriented graphs

  • Authors:
  • Luke Kelly;Daniela Kühn;Deryk Osthus

  • Affiliations:
  • School of Mathematics, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK;School of Mathematics, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK;School of Mathematics, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK

  • Venue:
  • Journal of Combinatorial Theory Series B
  • Year:
  • 2010

Quantified Score

Hi-index 0.00

Visualization

Abstract

We show that for each @?=4 every sufficiently large oriented graph G with @d^+(G),@d^-(G)=@?|G|/3@?+1 contains an @?-cycle. This is best possible for all those @?=4 which are not divisible by 3. Surprisingly, for some other values of @?, an @?-cycle is forced by a much weaker minimum degree condition. We propose and discuss a conjecture regarding the precise minimum degree which forces an @?-cycle (with @?=4 divisible by 3) in an oriented graph. We also give an application of our results to pancyclicity and consider @?-cycles in general digraphs.