Catalan structures arising from pattern-avoiding Stoimenow matchings and other Fishburn objects

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Hauptverfasser: Lv, Shuzhen, Kitaev, Sergey, Zhang, Philip B.
Format: Preprint
Veröffentlicht: 2025
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author Lv, Shuzhen
Kitaev, Sergey
Zhang, Philip B.
author_facet Lv, Shuzhen
Kitaev, Sergey
Zhang, Philip B.
contents In connection with Vassiliev's knot invariants, Stoimenow introduced in 1998 a class of matchings, also known as regular linearized chord diagrams. These matchings are linked to various combinatorial structures, all of which are associated with the Fishburn numbers. In this paper, we address a problem posed by Bevan et~al.\ concerning the identification of subsets of Stoimenow matchings that are counted by the Catalan numbers. We present five solutions in terms of pattern-avoiding matchings. We also consider four infinite families of patterns that generalize four of the five forbidden patterns appearing in the solution to the problem we solved and prove that the matchings avoiding them are equinumerous. Finally, we establish numerous results on distributions and joint equidistribution of statistics over Catalan-counted subsets of Fishburn structures, namely Stoimenow matchings, $(2+2)$-free posets, ascent sequences, and Fishburn permutations, notably expressing some of them in terms of Narayana numbers and others in terms of ballot numbers.
format Preprint
id arxiv_https___arxiv_org_abs_2509_09115
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Catalan structures arising from pattern-avoiding Stoimenow matchings and other Fishburn objects
Lv, Shuzhen
Kitaev, Sergey
Zhang, Philip B.
Combinatorics
05A05, 05A15
In connection with Vassiliev's knot invariants, Stoimenow introduced in 1998 a class of matchings, also known as regular linearized chord diagrams. These matchings are linked to various combinatorial structures, all of which are associated with the Fishburn numbers. In this paper, we address a problem posed by Bevan et~al.\ concerning the identification of subsets of Stoimenow matchings that are counted by the Catalan numbers. We present five solutions in terms of pattern-avoiding matchings. We also consider four infinite families of patterns that generalize four of the five forbidden patterns appearing in the solution to the problem we solved and prove that the matchings avoiding them are equinumerous. Finally, we establish numerous results on distributions and joint equidistribution of statistics over Catalan-counted subsets of Fishburn structures, namely Stoimenow matchings, $(2+2)$-free posets, ascent sequences, and Fishburn permutations, notably expressing some of them in terms of Narayana numbers and others in terms of ballot numbers.
title Catalan structures arising from pattern-avoiding Stoimenow matchings and other Fishburn objects
topic Combinatorics
05A05, 05A15
url https://arxiv.org/abs/2509.09115