3 papers
math.CO2026
On a conjecture concerning two-stack sortable permutations
Yongzhou Wen, Sherry H. F. Yan
The two-stack sortable permutations of length are known to be equinumerous with permutations of length avoiding the dashed patterns and $2\te…
math.CO2026
Bijective proofs of several conjectures on Jacobi permutations
Zhicong Lin, Yongzhou Wen, Sherry H. F. Yan
Jacobi permutations, invented by Viennot in the context of the Jacobi elliptic functions, are counted by the Euler numbers. Recently, Henke, Hoffman, Stephens, Yuan, and Zhuang stu…
math.CO2026
Further refinements of Euler-Mahonian statistics for multipermutations
Kaimei Huang, Yongzhou Wen, Sherry H. F. Yan
Permutation statistics constitute a classical subject of enumerative combinatorics. In her study of the genus zeta function, Denert discovered a new Mahonian statistic for permutat…