Combinatorial proofs of inverse relations and log-concavity for Bessel numbers
Abstract
Let the Bessel number of the second kind B(n,k) be the number of set partitions of [n] into k blocks of size one or two, and let the Bessel number of the first kind b(n,k) be a certain coefficient in n-th Bessel polynomial. In this paper, we show that Bessel numbers satisfy two properties of Stirling numbers: The two kinds of Bessel numbers are related by inverse formulas, and both Bessel numbers of the first kind and the second kind form log-concave sequences. By constructing sign-reversing involutions, we prove the inverse formulas. We review Krattenthaler's injection for the log-concavity of Bessel numbers of the second kind, and give a new explicit injection for the log-concavity of signless Bessel numbers of the first kind.
Keywords
Cite
@article{arxiv.math/0406378,
title = {Combinatorial proofs of inverse relations and log-concavity for Bessel numbers},
author = {Hyuk Han and Seunghyun Seo},
journal= {arXiv preprint arXiv:math/0406378},
year = {2007}
}
Comments
9 pages, 4 figures