arXiv subjects

Yanni Pei

Publications and source records attributed to Yanni Pei.

3 recordsLinked to original sources

arXiv2023

Counting derangements with signed right-to-left minima and excedances

Recently Alexandersson and Getachew proved some multivariate generalizations of a formula for enumerating signed excedances in derangements. In this paper we first relate their work to a recent continued fraction for permutations and confirm some of their observations. Our second main result is two refinements of their multivariate identities, which clearly explain the meaning of each term in their main formulas. We also explore some similar formulas for permutations of type B.

math.CO↗

arXiv2023

Analytic combinatorics of coordination numbers of cubic lattices

We investigate coordination numbers of the cubic lattices with emphases on their analytic behaviors, including the total positivity of the coordination matrices, the distribution of zeros of the coordination polynomials, the asymptotic normality of the coefficients of the coordination polynomials, the log-concavity and the log-convexity of the coordination numbers.

math.CO↗

arXiv2023

Positivity problem of three-term recurrence sequences

We present some necessary and/or sufficient conditions for the positivity problem of three-term recurrence sequences. As applications we show the positivity of diagonal Taylor coefficients of some rational functions in a unified approach. We also establish a criterion for the positivity and log-convexity of such sequences.

math.CO↗