2 papers
math.CO2004
A combinatorial proof of Postnikov's identity and a generalized enumeration of labeled trees
Seunghyun Seo
In this paper, we give a simple combinatorial explanation of a formula of A. Postnikov relating bicolored rooted trees to bicolored binary trees. We also present generalized formul…
math.CO2004
Combinatorial proofs of inverse relations and log-concavity for Bessel numbers
Hyuk Han, Seunghyun Seo
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 cer…