English

On the number of mth roots of permutations

Combinatorics 2012-01-26 v4

Abstract

Let m be a fixed positive integer. It is well-known that a permutation σ\sigma may have one, many, or no mth roots. In this note we provide an explicit expression and a generating function for the number of mth roots of \sigma. Let p_m(n) be the probability that a random n-permutation has an mth root. We also include a proof that p_m(jq)=p_m(jq+1)=... =p_m(jq+(q-1)) where j=0,1,... and m is a power of prime q.

Keywords

Cite

@article{arxiv.1005.1531,
  title  = {On the number of mth roots of permutations},
  author = {Jesús Leaños and Rutilo Moreno and Luis Manuel Rivera-Martínez},
  journal= {arXiv preprint arXiv:1005.1531},
  year   = {2012}
}

Comments

16 pages. Revised version, one subsection added. To appear in Australas J. Combinatorics