Fixed points and excedances in restricted permutations
组合数学
2007-05-23 v1
摘要
In this paper we prove that among the permutations of length n with i fixed points and j excedances, the number of 321-avoiding ones equals the number of 132-avoiding ones, for all given i,j<=n. We use a new technique involving diagonals of non-rational generating functions. This theorem generalizes a recent result of Robertson, Saracino and Zeilberger, for which we also give another, more direct proof.
引用
@article{arxiv.math/0212221,
title = {Fixed points and excedances in restricted permutations},
author = {Sergi Elizalde},
journal= {arXiv preprint arXiv:math/0212221},
year = {2007}
}
备注
12 pages, 10 figures, submitted to FPSAC'03