Abstract
We introduce the notion of the descent set polynomial as an alternative way of encoding the sizes of descent classes of permutations. Descent set polynomials exhibit interesting factorization patterns. We explore the question of when particular cyclotomic factors divide these polynomials. As an instance we deduce that the proportion of odd entries in the descent set statistics in the symmetric group Sn only depends on the number on 1's in the binary expansion of n. We observe similar properties for the signed descent set statistics.
Original language | English (US) |
---|---|
Pages (from-to) | 247-264 |
Number of pages | 18 |
Journal | Journal of Combinatorial Theory. Series A |
Volume | 116 |
Issue number | 2 |
DOIs | |
State | Published - Feb 2009 |
Bibliographical note
Funding Information:The authors thank the referee for improving the proof of Theorem 2.1. The authors also thank the MIT Mathematics Department where this research was carried out. The second author was partially supported by National Security Agency grant H98230-06-1-0072, and the third author was partially supported by National Science Foundation grant DMS-0604423.
Keywords
- Cyclotomic polynomials
- Descent set statistics
- Fermat primes
- Kummer's theorem
- Multivariate cd-index
- Permutations
- Quasisymmetric functions
- Signed permutations
- Type B quasisymmetric functions