Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
4653310 | European Journal of Combinatorics | 2016 | 13 Pages |
Abstract
A hex tree is an ordered tree of which each vertex has updegree 00, 11, or 22, and an edge from a vertex of updegree 11 is either left, median, or right. We present a refined enumeration of symmetric hex trees via a generalized binomial transform. It turns out that the refinement has a natural combinatorial interpretation by means of supertrees. We describe a bijection between symmetric hex trees and a certain class of supertrees. Some algebraic properties of the polynomials obtained in this procedure are also studied.
Related Topics
Physical Sciences and Engineering
Mathematics
Discrete Mathematics and Combinatorics
Authors
Hana Kim, Richard P. Stanley,