3 papers
math.CO2025
Pseudo-involutions in the Riordan group and Chebyshev polynomials
Alexander Burstein, Louis W. Shapiro
Generalizing the results in our previous paper, we consider pseudo-involutions in the Riordan group where the generating function for the first column of a Riordan array satisf…
math.CO2025
Distribution of sets of descent tops and descent bottoms on restricted permutations
Alexander Burstein
In this note, we prove some and conjecture other results regarding the distribution of descent top and descent bottom sets on some pattern-avoiding permutations. In particular, for…
math.CO2024
On (shape-)Wilf-equivalence of certain sets of (partially ordered) patterns
Alexander Burstein, Tian Han, Sergey Kitaev +1
We prove a conjecture of Gao and Kitaev on Wilf-equivalence of sets of patterns {12345,12354} and {45123,45213} that extends the list of 10 related conjectures proved in the litera…