Enumerating Permutations by their Run Structure

Christopher. J. Fewster, Daniel Siemssen

Research output: Contribution to journalArticlepeer-review

Abstract

Motivated by a problem in quantum field theory, we study the up and down structure of circular and linear permutations. In particular, we count the length of the (alternating) runs of permutations by representing them as monomials and find that they can always be decomposed into so-called `atomic' permutations introduced in this work. This decomposition allows us to enumerate the (circular) permutations of a subset of the natural numbers by the length of their runs. Furthermore, we rederive, in an elementary way and using the methods developed here, a result due to Kitaev on the enumeration of valleys.
Original languageEnglish
Article numberP4.18
Number of pages19
JournalELECTRONIC JOURNAL OF COMBINATORICS
Volume21
Issue number4
Publication statusPublished - 23 Oct 2014

Bibliographical note

19 pages

Keywords

  • Enumerative combinatorics
  • permutations

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