1 citations · 1 across the 8 of their papers we have counts for
10 papers
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 $2\te…
The -analogues of -positivity of Eulerian polynomials via group actions
Taifeng Ding, Lintong Wang, Sherry H. F. Yan
Han, Jouhet and Zeng established -analogues of the -expansion formulas for Eulerian polynomials of types and . Combinatorial interpretations of the corresponding coeff…
On two conjectures concerning special kinds of descents on permutations
Taifeng Ding, Sherry H. F. Yan
In this paper, we prove the continued fraction conjecture posed by Han, Mao and Zeng for the generating function of permutations with respect to the number of descents of type …
Bijective proofs of several conjectures on Jacobi permutations
Zhicong Lin, Yongzhou Wen, Sherry H. F. Yan
Jacobi permutations, invented by Viennot in the context of the Jacobi elliptic functions, are counted by the Euler numbers. Recently, Henke, Hoffman, Stephens, Yuan, and Zhuang stu…
Further refinements of Euler-Mahonian statistics for multipermutations
Kaimei Huang, Yongzhou Wen, Sherry H. F. Yan
Permutation statistics constitute a classical subject of enumerative combinatorics. In her study of the genus zeta function, Denert discovered a new Mahonian statistic for permutat…
Further results on -Euler-Mahonian statistics
Kaimei Huang, Sherry H. F. Yan
As natural generalizations of the descent number ($\des$) and the major index ($\maj$), Rawlings introduced the notions of the -descent number ($r\des$) and the -major index…
Combinatorics on bi--positivity of -Eulerian polynomials
Sherry H. F. Yan, Xubo Yang, Zhicong Lin
The -Eulerian polynomials were introduced as ascent polynomials over -inversion sequences by Savage and Viswanathan. The bi--positivity of the -Eul…
Bijections around Springer numbers
Shaoshi Chen, Yang Li, Zhicong Lin +1
Arnol'd proved in 1992 that Springer numbers enumerate the Snakes, which are type analogs of alternating permutations. Chen, Fan and Jia in 2011 introduced the labeled ballot p…
Parity statistics on restricted permutations and the Catalan--Schett polynomials
Zhicong Lin, Jing Liu, Sherry H. F. Yan
Motivated by Kitaev and Zhang's recent work on non-overlapping ascents in stack-sortable permutations and Dumont's permutation interpretation of the Jacobi elliptic functions, we i…
On a conjecture concerning the -Euler-Mahonian statistic on permutations
Kaimei Huang, Zhicong Lin, Sherry H. F. Yan
A pair of permutation statistics is said to be -Euler-Mahonian if and , are e…