Rational generating series for affine permutation pattern avoidance

Autor: Jones, Brant
Rok vydání: 2015
Předmět:
Druh dokumentu: Working Paper
Popis: We consider the set of affine permutations that avoid a fixed permutation pattern. Crites has given a simple characterization for when this set is infinite. We find the generating series for this set using the Coxeter length statistic and prove that it can always be represented as a rational function. We also give a characterization of the patterns for which the coefficients of the generating series are periodic. The proofs exploit a new polyhedral encoding for the affine symmetric group.
Comment: 15 pages
Databáze: arXiv