3 papers
math.CO2026
Descent Tops and Pinnacles on 2143- and 3421-Avoiding Permutations
Yue Dong, Lily Li Liu, Tongyuan Zhao
We prove the 2143-3421 case of Burstein's conjecture on the distribution of descent-top sets by constructing an explicit bijection between the two avoidance classes. The bijection…
math.CO2025
An identity relating Catalan numbers to tangent numbers with arithmetic applications
Tongyuan Zhao, Zhicong Lin, Yongchun Zang
We prove a combinatorial identity relating Catalan numbers to tangent numbers arising from the study of peak algebra that was conjectured by Aliniaeifard and Li. This identity lead…
math.CO2023
Two involutions on binary trees and generalizations
Yang Li, Zhicong Lin, Tongyuan Zhao
This paper investigates two involutions on binary trees. One is the mirror symmetry of binary trees which combined with the classical bijection between binary trees and plane t…