2 papers
math.CO2011
On Han's Hook Length Formulas for Trees
William Y. C. Chen, Oliver X. Q. Gao, Peter L. Guo
Recently, Han obtained two hook length formulas for binary trees and asked for combinatorial proofs. One of Han's formulas has been generalized to k-ary trees by Yang. Sagan has fo…
math.CO2009
Hook Length Formulas for Trees by Han's Expansion
William Y. C. Chen, Oliver X. Q. Gao, Peter L. Guo
Recently Han obtained a general formula for the weight function corresponding to the expansion of a generating function in terms of hook lengths of binary trees. In this paper, we…