English

Some natural extensions of the parking space

Combinatorics 2020-03-10 v1

Abstract

We construct a family of SnS_n modules indexed by c{1,,n}c\in\{1,\dots,n\} with the property that upon restriction to Sn1S_{n-1} they recover the classical parking function representation of Haiman. The construction of these modules relies on an SnS_n-action on a set that is closely related to the set of parking functions. We compute the characters of these modules and use the resulting description to classify them up to isomorphism. In particular, we show that the number of isomorphism classes is equal to the number of divisors dd of nn satisfying d2( ⁣ ⁣ ⁣ ⁣mod4) d\neq 2 \: (\!\!\!\!\mod 4). In the cases c=nc=n and c=1c=1, we compute the number of orbits. Based on empirical evidence, we conjecture that when c=1c=1, our representation is hh-positive and is in fact the (ungraded) extension of the parking function representation constructed by Berget and Rhoades.

Keywords

Cite

@article{arxiv.2003.04134,
  title  = {Some natural extensions of the parking space},
  author = {Matjaž Konvalinka and Vasu Tewari},
  journal= {arXiv preprint arXiv:2003.04134},
  year   = {2020}
}

Comments

16 pages; comments welcome