{ "id": "2309.05903", "version": "v1", "published": "2023-09-12T01:24:55.000Z", "updated": "2023-09-12T01:24:55.000Z", "title": "Interlacing property of a family of generating polynomials over Dyck paths", "authors": [ "Bo Wang", "Candice X. T. Zhang" ], "categories": [ "math.CO" ], "abstract": "In the study of a tantalizing symmetry on Catalan objects, B\\'ona et al. introduced a family of polynomials $\\{W_{n,k}(x)\\}_{n\\geq k\\geq 0}$ defined by \\begin{align*} W_{n,k}(x)=\\sum_{m=0}^{k}w_{n,k,m}x^{m}, \\end{align*} where $w_{n,k,m}$ counts the number of Dyck paths of semilength $n$ with $k$ occurrences of $UD$ and $m$ occurrences of $UUD$. They proposed two conjectures on the interlacing property of these polynomials, one of which states that $\\{W_{n,k}(x)\\}_{n\\geq k}$ is a Sturm sequence for any fixed $k\\geq 1$, and the other states that $\\{W_{n,k}(x)\\}_{1\\leq k\\leq n}$ is a Sturm-unimodal sequence for any fixed $n\\geq 1$. In this paper, we obtain certain recurrence relations for $W_{n,k}(x)$, and further confirm their conjectures.", "revisions": [ { "version": "v1", "updated": "2023-09-12T01:24:55.000Z" } ], "analyses": { "keywords": [ "dyck paths", "interlacing property", "generating polynomials", "recurrence relations", "occurrences" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }