6 papers
Decreasing Runs in Quasi-Stirling Permutations of Multisets
Hanqian Fang
As a natural extension of Stirling permutations, quasi-Stirling permutations are multipermutations with the property that for any subsequence sat…
Stable patterns on permutations of multisets
Shaoshi Chen, Hanqian Fang, Sergey Kitaev
In this paper, we study patterns on permutations of multisets whose multivariate distribution generating functions are symmetric. We interpret this phenomenon through the lens of g…
On the Summability Problem of Multivariate Rational Functions in the Mixed Case
Shaoshi Chen, Lixin Du, Hanqian Fang +1
Continuing previous work, this paper focuses on the summability problem of multivariate rational functions in the mixed case in which both shift and -shift operators can appear.…
A zero-test for D-algebraic transseries
Shaoshi Chen, Hanqian Fang, Joris van der Hoeven
Consider formal power series that are defined as the solutions of a system of polynomial differential equations together with a sufficient numbe…
Analytic properties arising from the Baxter numbers
Hanqian Fang, Candice X. T. Zhang, James J. Y. Zhao
Baxter numbers are known as the enumeration of Baxter permutations and numerous other discrete structures, playing a significant role across combinatorics, algebra, and analysis. I…
Patterns in Multi-dimensional Permutations
Shaoshi Chen, Hanqian Fang, Sergey Kitaev +1
In this paper, we propose a general framework that extends the theory of permutation patterns to higher dimensions and unifies several combinatorial objects studied in the literatu…