activity
20242026
collaborators

6 papers

math.CO2026

Combinatorial proofs of some identities on overpartitions with repeated smallest non-overlined part

Nayandeep Deka Baruah, Haijun Li, Pankaj Jyoti Mahanta

Let denote the number of overpartitions of where the smallest non-overlined part, say , appears times and every overlined part is bigge…

math.ST2025

Operator Tail Densities of Multivariate Copulas

Haijun Li

Operator regular variation of a multivariate distribution can be decomposed into the operator tail dependence of the underlying copula and the regular variation of the univariate m…

math.CO2025

Sequences of odd length in strict partitions IV: the combinatorics of parameterized Rogers-Ramanujan type identities

Haijun Li

In the first three papers, we conducted a series of discussions on the statistics of strict partitions and Rogers-Ramanujan partitions, specifically the sequences of odd length (de…

math.CO2025

The combinatorics of identities involving overpartitions with distinct parts

Haijun Li

Recently, Andrews and EI Bachraoui discovered several companions for some famous -series formulas, and derived some new identities involving partitions and overpartitions with d…

math.PR2025

Toward a Hazard Rate Framework for Regular and Rapid Variation

Haijun Li

Regular and rapid variation have been extensively studied in the literature and applied across various fields, particularly in extreme value theory. In this paper, we examine regul…

math.PR2024

Tail Dependence of Multivariate Archimedean Copulas

Haijun Li

Archimedean copulas generated by Laplace transforms have been extensively studied in the literature, with much of the focus on tail dependence limited only to cases where the Lapla…