The number of $k$-parallelogram polyominoes

A convex polyomino is $k$-$\textit{convex}$ if every pair of its cells can be connected by means of a $\textit{monotone path}$, internal to the polyomino, and having at most $k$ changes of direction. The number $k$-convex polyominoes of given semi-perimeter has been determined only for small values...

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Main Authors: Daniela Battaglino, Jean-Marc Fédou, Simone Rinaldi, Samanta Socci
Format: Article
Language:English
Published: Discrete Mathematics & Theoretical Computer Science 2013-01-01
Series:Discrete Mathematics & Theoretical Computer Science
Subjects:
Online Access:https://dmtcs.episciences.org/2370/pdf
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author Daniela Battaglino
Jean-Marc Fédou
Simone Rinaldi
Samanta Socci
author_facet Daniela Battaglino
Jean-Marc Fédou
Simone Rinaldi
Samanta Socci
author_sort Daniela Battaglino
collection DOAJ
description A convex polyomino is $k$-$\textit{convex}$ if every pair of its cells can be connected by means of a $\textit{monotone path}$, internal to the polyomino, and having at most $k$ changes of direction. The number $k$-convex polyominoes of given semi-perimeter has been determined only for small values of $k$, precisely $k=1,2$. In this paper we consider the problem of enumerating a subclass of $k$-convex polyominoes, precisely the $k$-$\textit{convex parallelogram polyominoes}$ (briefly, $k$-$\textit{parallelogram polyominoes}$). For each $k \geq 1$, we give a recursive decomposition for the class of $k$-parallelogram polyominoes, and then use it to obtain the generating function of the class, which turns out to be a rational function. We are then able to express such a generating function in terms of the $\textit{Fibonacci polynomials}$.
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spelling doaj.art-3e0d86ce64574a599af73a52947906b62024-03-07T14:52:36ZengDiscrete Mathematics & Theoretical Computer ScienceDiscrete Mathematics & Theoretical Computer Science1365-80502013-01-01DMTCS Proceedings vol. AS,...Proceedings10.46298/dmtcs.23702370The number of $k$-parallelogram polyominoesDaniela Battaglino0Jean-Marc Fédou1Simone Rinaldi2https://orcid.org/0000-0003-3377-5331Samanta Socci3Laboratoire d'Informatique, Signaux, et Systèmes de Sophia-Antipolis (I3S) / Equipe MC3Laboratoire d'Informatique, Signaux, et Systèmes de Sophia-Antipolis (I3S) / Equipe MC3Dipartimento di Matematica e Informatica [Siena]Dipartimento di Matematica e Informatica [Siena]A convex polyomino is $k$-$\textit{convex}$ if every pair of its cells can be connected by means of a $\textit{monotone path}$, internal to the polyomino, and having at most $k$ changes of direction. The number $k$-convex polyominoes of given semi-perimeter has been determined only for small values of $k$, precisely $k=1,2$. In this paper we consider the problem of enumerating a subclass of $k$-convex polyominoes, precisely the $k$-$\textit{convex parallelogram polyominoes}$ (briefly, $k$-$\textit{parallelogram polyominoes}$). For each $k \geq 1$, we give a recursive decomposition for the class of $k$-parallelogram polyominoes, and then use it to obtain the generating function of the class, which turns out to be a rational function. We are then able to express such a generating function in terms of the $\textit{Fibonacci polynomials}$.https://dmtcs.episciences.org/2370/pdfconvex polyominoesl-convex polyominoesrational generating functionsfibonacci polynomials[info.info-dm] computer science [cs]/discrete mathematics [cs.dm]
spellingShingle Daniela Battaglino
Jean-Marc Fédou
Simone Rinaldi
Samanta Socci
The number of $k$-parallelogram polyominoes
Discrete Mathematics & Theoretical Computer Science
convex polyominoes
l-convex polyominoes
rational generating functions
fibonacci polynomials
[info.info-dm] computer science [cs]/discrete mathematics [cs.dm]
title The number of $k$-parallelogram polyominoes
title_full The number of $k$-parallelogram polyominoes
title_fullStr The number of $k$-parallelogram polyominoes
title_full_unstemmed The number of $k$-parallelogram polyominoes
title_short The number of $k$-parallelogram polyominoes
title_sort number of k parallelogram polyominoes
topic convex polyominoes
l-convex polyominoes
rational generating functions
fibonacci polynomials
[info.info-dm] computer science [cs]/discrete mathematics [cs.dm]
url https://dmtcs.episciences.org/2370/pdf
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