Diameters of Cayley graphs of Chevalley groups

  • Authors:
  • M. Kassabov;T. R. Riley

  • Affiliations:
  • Department of Mathematics, Cornell University, 310 Malott Hall, Ithaca, NY 14853, USA;Department of Mathematics, Cornell University, 310 Malott Hall, Ithaca, NY 14853, USA

  • Venue:
  • European Journal of Combinatorics
  • Year:
  • 2007

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Abstract

We show that for integers k=2 and n=3, the diameter of the Cayley graph of SL"n(Z/kZ) associated with a standard two-element generating set is at most a constant times n^2lnk. This answers a question of A. Lubotzky concerning SL"n(F"p) and is unexpected because these Cayley graphs do not form an expander family. Our proof amounts to a quick algorithm for finding short words representing elements of SL"n(Z/kZ). We generalize our results to other Chevalley groups over Z/kZ.