A pattern theorem for random sorting networks

A sorting network is a shortest path from 12⋯n to n⋯21 in the Cayley graph of the symmetric group S[subscript n] generated by nearest-neighbor swaps. A pattern is a sequence of swaps that forms an initial segment of some sorting network. We prove that in a uniformly random n-element sorting network,...

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Bibliographic Details
Main Authors: Angel, Omer, Gorin, Vadim, Holroyd, Alexander E
Other Authors: Massachusetts Institute of Technology. Department of Mathematics
Format: Article
Language:en_US
Published: Institute of Mathematical Statistics 2014
Online Access:http://hdl.handle.net/1721.1/89523
https://orcid.org/0000-0002-9828-5862
Description
Summary:A sorting network is a shortest path from 12⋯n to n⋯21 in the Cayley graph of the symmetric group S[subscript n] generated by nearest-neighbor swaps. A pattern is a sequence of swaps that forms an initial segment of some sorting network. We prove that in a uniformly random n-element sorting network, any fixed pattern occurs in at least cn[superscript 2] disjoint space-time locations, with probability tending to 1 exponentially fast as n→∞. Here c is a positive constant which depends on the choice of pattern. As a consequence, the probability that the uniformly random sorting network is geometrically realizable tends to 0.