Enumeration of pattern-avoiding $(0,1)$-matrices and their symmetry classes

Fuente: arXiv
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Autores principales: Eu, Sen-Peng, Lee, Yi-Lin
Formato: Preprint
Publicado: 2025
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author Eu, Sen-Peng
Lee, Yi-Lin
author_facet Eu, Sen-Peng
Lee, Yi-Lin
contents Recently, Brualdi and Cao studied $I_k$-avoiding $(0,1)$-matrices by decomposing them into zigzag paths and proved that the maximum number of $1$'s in such a matrix is given by an exact formula. We further study the structure of maximal $I_k$-avoiding $(0,1)$-matrices (IAMs) by interpreting them as families of non-intersecting lattice paths on the square lattice. Using this perspective, we establish a bijection showing that IAMs are equinumerous with plane partitions of a certain size. Moreover, we classify all ten symmetry classes of IAMs under the action of the dihedral group of order $8$ and show that the enumeration formulas for these classes are given by simple product formulas. Extending this approach to skew shapes, we derive a conceptual formula for enumerating maximal $I_k$-avoiding $(0,1)$-fillings of skew shapes.
format Preprint
id arxiv_https___arxiv_org_abs_2510_26168
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Enumeration of pattern-avoiding $(0,1)$-matrices and their symmetry classes
Eu, Sen-Peng
Lee, Yi-Lin
Combinatorics
05A05, 05A15, 05A19, 05B20
Recently, Brualdi and Cao studied $I_k$-avoiding $(0,1)$-matrices by decomposing them into zigzag paths and proved that the maximum number of $1$'s in such a matrix is given by an exact formula. We further study the structure of maximal $I_k$-avoiding $(0,1)$-matrices (IAMs) by interpreting them as families of non-intersecting lattice paths on the square lattice. Using this perspective, we establish a bijection showing that IAMs are equinumerous with plane partitions of a certain size. Moreover, we classify all ten symmetry classes of IAMs under the action of the dihedral group of order $8$ and show that the enumeration formulas for these classes are given by simple product formulas. Extending this approach to skew shapes, we derive a conceptual formula for enumerating maximal $I_k$-avoiding $(0,1)$-fillings of skew shapes.
title Enumeration of pattern-avoiding $(0,1)$-matrices and their symmetry classes
topic Combinatorics
05A05, 05A15, 05A19, 05B20
url https://arxiv.org/abs/2510.26168