Self-embedding similitudes of Bedford-McMullen carpets with dependent ratios

Fuente: arXiv
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Main Author: Xiao, Jian-Ci
Format: Preprint
Published: 2024
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author Xiao, Jian-Ci
author_facet Xiao, Jian-Ci
contents We prove that any non-degenerate Bedford-McMullen carpet does not admit oblique self-embedding similitudes; that is, if $f$ is a similitude sending the carpet into itself, then the image of the $x$-axis under $f$ must be parallel to one of the principal axes. This result leads to a logarithmic commensurability result on the contraction ratios of such embeddings, completing a previous study by Algom and Hochman [Ergod. Th. & Dynam. Sys. 39 (2019), 577-603] on Bedford-McMullen carpets generated by multiplicatively independent exponents. Our approach also provides a new proof of their non-obliqueness statement that avoids analyzing the tangent sets. For the self-similar case, however, we construct a generalized Sierpiński carpet that is symmetric with respect to an appropriate oblique line and hence admits a reflectional oblique self-embedding. As a complement, we prove that if a generalized Sierpiński carpet satisfies the strong separation condition and permits an oblique rotational self-embedding similitude, then the tangent of the rotation angle takes values $\pm 1$.
format Preprint
id arxiv_https___arxiv_org_abs_2412_02123
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Self-embedding similitudes of Bedford-McMullen carpets with dependent ratios
Xiao, Jian-Ci
Classical Analysis and ODEs
Metric Geometry
Primary 28A80, Secondary 28A78
We prove that any non-degenerate Bedford-McMullen carpet does not admit oblique self-embedding similitudes; that is, if $f$ is a similitude sending the carpet into itself, then the image of the $x$-axis under $f$ must be parallel to one of the principal axes. This result leads to a logarithmic commensurability result on the contraction ratios of such embeddings, completing a previous study by Algom and Hochman [Ergod. Th. & Dynam. Sys. 39 (2019), 577-603] on Bedford-McMullen carpets generated by multiplicatively independent exponents. Our approach also provides a new proof of their non-obliqueness statement that avoids analyzing the tangent sets. For the self-similar case, however, we construct a generalized Sierpiński carpet that is symmetric with respect to an appropriate oblique line and hence admits a reflectional oblique self-embedding. As a complement, we prove that if a generalized Sierpiński carpet satisfies the strong separation condition and permits an oblique rotational self-embedding similitude, then the tangent of the rotation angle takes values $\pm 1$.
title Self-embedding similitudes of Bedford-McMullen carpets with dependent ratios
topic Classical Analysis and ODEs
Metric Geometry
Primary 28A80, Secondary 28A78
url https://arxiv.org/abs/2412.02123