Catalan words avoiding a pattern of length four

Authors

  • Jean-Luc Baril Universite de Bourgogne
  • Toufik Mansour University of Haifa
  • Jose L. Ramirez Universidad Nacional de Colombia
  • Mark Shattuck University of Tennessee

DOI:

https://doi.org/10.55016/g3gszf44

Abstract

Let $\mathcal{C}_n$ denote the set of Catalan words of length $n$ and $\mathcal{C}_n(p)$ the subset of $\mathcal{C}_n$ whose members avoid the pattern $p$. In this paper, we enumerate members of $\mathcal{C}_n(p)$ where $p$ is a permutation pattern of length four. This extends recent work on Catalan words concerning the avoidance of classical, consecutive or vincular patterns of length at most three. Indeed, we determine the generating function of the distribution for the number of descents on each of the corresponding avoidance classes. We make use of the symbolic counting method to establish our results, together with a variety of other enumerative techniques, including use of strategic decompositions, introduction of auxiliary generating functions and analysis of active sites.

Author Biographies

  • Jean-Luc Baril, Universite de Bourgogne

    Department of Mathematics - Professor

  • Toufik Mansour, University of Haifa

    Department of Mathematics - Professor

  • Jose L. Ramirez, Universidad Nacional de Colombia

    Department of Mathematics - Associate Professor

  • Mark Shattuck, University of Tennessee

    Department of Mathematics - Adjunct research assistant professor and lecturer

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Published

2026-10-12

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Section

Articles