On the time and the bit complexity of distributed randomised anonymous ring colouring

  • Authors:
  • Y. Métivier;J. M. Robson;N. Saheb-Djahromi;A. Zemmari

  • Affiliations:
  • -;-;-;-

  • Venue:
  • Theoretical Computer Science
  • Year:
  • 2013

Quantified Score

Hi-index 5.23

Visualization

Abstract

We present and analyse a very simple randomised distributed vertex colouring algorithm for ring graphs. Its time complexity is log"2n+o(logn) on average and 2log"2n+o(logn) with probability 1-o(n^-^1). Since each message contains one bit, we deduce the same values for its bit complexity. Then we combine this algorithm with another and we obtain a 3-colouring algorithm for ring graphs. Thanks to an overlapping, we obtain once more the same values for the time complexities on average and with probability 1-o(n^-^1). The same results hold for the bit complexity. These results are obtained using the Mellin transform. We establish lower bounds (on average and with probability 1-o(n^-^1)) for the distributed randomised anonymous ring colouring problem. We prove that our algorithms match these lower bounds modulo a negligible additive function (negligible with respect to log"2n). We assume that the ring is anonymous: unique identities are not available to distinguish the processes; we only assume that each vertex distinguishes between its neighbours. Furthermore, we do not assume that the size (or an upper bound on the size) of the ring is known.