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The (p,q)-Analogues of Bi-Stirling Eulerian Polynomials via continued fractions
Abstract
We establish Jacobi-type continued fraction expansions for (p,q)-analogues of the bi-Stirling Eulerian polynomials, which refine classical Eulerian statistics on permutations. These polynomials admit equivalent definitions in terms of descents or excedances. The parameters p and q encode refined permutation statistics, including (ldes,rasc) and (cros,nest). Our approach is based on weighted Motzkin path models arising from variants of the bijections of Françon--Viennot and Foata--Zeilberger. As applications, we obtain new results on total positivity and gamma-positivity for several families of enumerative polynomials. Our results unify and extend a number of recent works in the literature.
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BibTeX
@misc{xu2026pqanalogues,
title = {{The (p,q)-Analogues of Bi-Stirling Eulerian Polynomials via continued fractions}},
author = {Chao Xu and Jiang Zeng},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.14386},
eprint = {2609.14386},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.14386},
}
RIS
TY - UNPB
TI - The (p,q)-Analogues of Bi-Stirling Eulerian Polynomials via continued fractions
AU - Chao Xu
AU - Jiang Zeng
PY - 2026
DA - 2026/09/13
PB - arXiv
DO - 10.48550/arxiv.2609.14386
UR - https://arxiv.org/abs/2609.14386
AB - We establish Jacobi-type continued fraction expansions for (p,q)-analogues of the bi-Stirling Eulerian polynomials, which refine classical Eulerian statistics on permutations. These polynomials admit equivalent definitions in terms of descents or excedances. The parameters p and q encode refined permutation statistics, including (ldes,rasc) and (cros,nest). Our approach is based on weighted Motzkin path models arising from variants of the bijections of Françon--Viennot and Foata--Zeilberger. As applications, we obtain new results on total positivity and gamma-positivity for several families of enumerative polynomials. Our results unify and extend a number of recent works in the literature.
ER -