Pattern-Avoidance in Binary Fillings of Grid Shapes (short version)

A $\textit{grid shape}$ is a set of boxes chosen from a square grid; any Young diagram is an example. This paper considers a notion of pattern-avoidance for $0-1$ fillings of grid shapes, which generalizes permutation pattern-avoidance. A filling avoids some patterns if none of its sub-shapes equal...

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Main Author: Alexey Spiridonov
Format: Article
Language:English
Published: Discrete Mathematics & Theoretical Computer Science 2008-01-01
Series:Discrete Mathematics & Theoretical Computer Science
Subjects:
Online Access:https://dmtcs.episciences.org/3610/pdf
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author Alexey Spiridonov
author_facet Alexey Spiridonov
author_sort Alexey Spiridonov
collection DOAJ
description A $\textit{grid shape}$ is a set of boxes chosen from a square grid; any Young diagram is an example. This paper considers a notion of pattern-avoidance for $0-1$ fillings of grid shapes, which generalizes permutation pattern-avoidance. A filling avoids some patterns if none of its sub-shapes equal any of the patterns. We focus on patterns that are $\textit{pairs}$ of $2 \times 2$ fillings. For some shapes, fillings that avoid specific $2 \times 2$ pairs are in bijection with totally nonnegative Grassmann cells, or with acyclic orientations of bipartite graphs. We prove a number of results analogous to Wilf-equivalence for these objects ―- that is, we show that for certain classes of shapes, some pattern-avoiding fillings are equinumerous with others.
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spelling doaj.art-18e2503823ab42a1aa99aac7c1f27a8c2024-03-07T14:38:06ZengDiscrete Mathematics & Theoretical Computer ScienceDiscrete Mathematics & Theoretical Computer Science1365-80502008-01-01DMTCS Proceedings vol. AJ,...Proceedings10.46298/dmtcs.36103610Pattern-Avoidance in Binary Fillings of Grid Shapes (short version)Alexey Spiridonov0Department of Mathematics [MIT]A $\textit{grid shape}$ is a set of boxes chosen from a square grid; any Young diagram is an example. This paper considers a notion of pattern-avoidance for $0-1$ fillings of grid shapes, which generalizes permutation pattern-avoidance. A filling avoids some patterns if none of its sub-shapes equal any of the patterns. We focus on patterns that are $\textit{pairs}$ of $2 \times 2$ fillings. For some shapes, fillings that avoid specific $2 \times 2$ pairs are in bijection with totally nonnegative Grassmann cells, or with acyclic orientations of bipartite graphs. We prove a number of results analogous to Wilf-equivalence for these objects ―- that is, we show that for certain classes of shapes, some pattern-avoiding fillings are equinumerous with others.https://dmtcs.episciences.org/3610/pdfpattern-avoidancefillinggrid shapele-diagramacyclic orientationyoung diagram[math.math-co] mathematics [math]/combinatorics [math.co][info.info-dm] computer science [cs]/discrete mathematics [cs.dm]
spellingShingle Alexey Spiridonov
Pattern-Avoidance in Binary Fillings of Grid Shapes (short version)
Discrete Mathematics & Theoretical Computer Science
pattern-avoidance
filling
grid shape
le-diagram
acyclic orientation
young diagram
[math.math-co] mathematics [math]/combinatorics [math.co]
[info.info-dm] computer science [cs]/discrete mathematics [cs.dm]
title Pattern-Avoidance in Binary Fillings of Grid Shapes (short version)
title_full Pattern-Avoidance in Binary Fillings of Grid Shapes (short version)
title_fullStr Pattern-Avoidance in Binary Fillings of Grid Shapes (short version)
title_full_unstemmed Pattern-Avoidance in Binary Fillings of Grid Shapes (short version)
title_short Pattern-Avoidance in Binary Fillings of Grid Shapes (short version)
title_sort pattern avoidance in binary fillings of grid shapes short version
topic pattern-avoidance
filling
grid shape
le-diagram
acyclic orientation
young diagram
[math.math-co] mathematics [math]/combinatorics [math.co]
[info.info-dm] computer science [cs]/discrete mathematics [cs.dm]
url https://dmtcs.episciences.org/3610/pdf
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