Are random permutations spherically uniform?

M. Perlman

Published 2020 in Electronic Journal of Probability

ABSTRACT

For large q, does the (discrete) uniform distribution on the set of q! permutations of the vector x̄ = (1, 2, . . . , q)′ closely approximate the (continuous) uniform distribution on the (q − 2)-sphere that contains them? These permutations comprise the vertices of the regular permutohedron, a (q − 1)-dimensional convex polyhedron. The answer is emphatically no: these permutations are confined to a negligible portion of the sphere, and the regular permutohedron occupies a negligible portion of the ball. However, (1, 2, . . . , q) is not the most favorable configuration for spherical uniformity of permutations. A more favorable configuration x̂ is found, namely that which minimizes the normalized surface area of the largest empty spherical cap among its q! permutations. Unlike that for x̄, the normalized surface area of the largest empty spherical cap among the permutations of x̂ approaches 0 as q →∞. Nonetheless the permutations of x̂ do not approach spherical uniformity either. The existence of an asymptotically spherically uniform permutation sequence remains an open question.

PUBLICATION RECORD

  • Publication year

    2020

  • Venue

    Electronic Journal of Probability

  • Publication date

    Unknown publication date

  • Fields of study

    Mathematics

  • Identifiers
  • External record

    Open on Semantic Scholar

  • Source metadata

    Semantic Scholar

CITATION MAP

EXTRACTION MAP

CLAIMS

  • No claims are published for this paper.

CONCEPTS

  • No concepts are published for this paper.

REFERENCES

Showing 1-20 of 20 references · Page 1 of 1

CITED BY

  • No citing papers are available for this paper.

Showing 0-0 of 0 citing papers · Page 1 of 1