中文

restricted 1-3-2 permutations and generalized patterns

组合数学 2007-05-23 v1

摘要

Recently, Babson and Steingrimsson (see [BS]) introduced generalized permutations patterns that allow the requirement that two adjacent letters in a pattern must be adjacent in the permutation. We study generating functions for the number of permutations on nn letters avoiding 1321-3-2 (or containing 1321-3-2 exactly once) and an arbitrary generalized pattern τ\tau on kk letters, or containing τ\tau exactly once. In several cases the generating function depends only on kk and is expressed via Chebyshev polynomials of the second kind, and generating function of Motzkin numbers.

关键词

引用

@article{arxiv.math/0110039,
  title  = {restricted 1-3-2 permutations and generalized patterns},
  author = {T. Mansour},
  journal= {arXiv preprint arXiv:math/0110039},
  year   = {2007}
}

备注

10 pages