A counter example on a Borsuk conjecture

The study of shape restrictions of subsets of Rd has several applications in many areas, being convexity, r-convexity, and positive reach, some of the most famous, and typically imposed in set estimation. The following problem was attributed to K. Borsuk, by J. Perkal in 1956: find an r-convex set w...

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Autor principal: Cholaquidis, Alejandro (author)
Formato: article
Lenguaje:inglés
Publicado: 2023
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Acceso en línea:https://hdl.handle.net/20.500.12008/37374
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author Cholaquidis, Alejandro
author_browse Cholaquidis, Alejandro
author_facet Cholaquidis, Alejandro
author_role author
collection COLIBRI
dc.contributor.none.fl_str_mv Cholaquidis Alejandro, Universidad de la República (Uruguay). Facultad de Ciencias. Centro de Matemática.
dc.creator.none.fl_str_mv Cholaquidis, Alejandro
dc.date.none.fl_str_mv 2023-06-02T14:26:16Z
2023-06-02T14:26:16Z
2023
dc.format.none.fl_str_mv 4 h
application/pdf
dc.identifier.none.fl_str_mv Cholaquidis, A. " A counter example on a Borsuk conjecture". Applied General Topology. [en línea] 2023, 24(1): 125-128. 4 h.
1989-4147
https://hdl.handle.net/20.500.12008/37374
10.4995/agt.2023.18176
dc.language.none.fl_str_mv en
eng
dc.publisher.none.fl_str_mv Universitat Politècnica de València
dc.relation.none.fl_str_mv Applied General Topology, 2023, 24(1): 125-128
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
Licencia Creative Commons Atribución - No Comercial - Sin Derivadas (CC - By-NC-ND 4.0)
dc.source.none.fl_str_mv reponame:COLIBRI
instname:Universidad de la República
instacron:Universidad de la República
dc.subject.none.fl_str_mv r-convex set
Locally contractible set
Positive reach
dc.title.none.fl_str_mv A counter example on a Borsuk conjecture
dc.type.none.fl_str_mv Artículo
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
description The study of shape restrictions of subsets of Rd has several applications in many areas, being convexity, r-convexity, and positive reach, some of the most famous, and typically imposed in set estimation. The following problem was attributed to K. Borsuk, by J. Perkal in 1956: find an r-convex set which is not locally contractible. Stated in that way is trivial to find such a set. However, if we ask the set to be equal to the closure of its interior (a condition fulfilled for instance if the set is the support of a probability distribution absolutely continuous with respect to the d-dimensional Lebesgue measure), the problem is much more difficult. We present a counter example of a not locally contractible set, which is r-convex. This also proves that the class of supports with positive reach of absolutely continuous distributions includes strictly the class of r-convex supports of absolutely continuous distributions.
eu_rights_str_mv openAccess
format article
id anni_0fa5907d15e510dea0a96c8a2d7d4153
identifier_str_mv Cholaquidis, A. " A counter example on a Borsuk conjecture". Applied General Topology. [en línea] 2023, 24(1): 125-128. 4 h.
1989-4147
10.4995/agt.2023.18176
instacron_str Universidad de la República
institution Universidad de la República
instname_str Universidad de la República
language eng
language_invalid_str_mv en
network_acronym_str anni
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oai_identifier_str oai:colibri.udelar.edu.uy:20.500.12008/37374
publishDate 2023
publishDateSort 2023
publisher.none.fl_str_mv Universitat Politècnica de València
reponame_str COLIBRI
repository.mail.fl_str_mv
repository.name.fl_str_mv
repository_id_str
rights_invalid_str_mv Licencia Creative Commons Atribución - No Comercial - Sin Derivadas (CC - By-NC-ND 4.0)
spelling A counter example on a Borsuk conjectureCholaquidis, Alejandror-convex setLocally contractible setPositive reachThe study of shape restrictions of subsets of Rd has several applications in many areas, being convexity, r-convexity, and positive reach, some of the most famous, and typically imposed in set estimation. The following problem was attributed to K. Borsuk, by J. Perkal in 1956: find an r-convex set which is not locally contractible. Stated in that way is trivial to find such a set. However, if we ask the set to be equal to the closure of its interior (a condition fulfilled for instance if the set is the support of a probability distribution absolutely continuous with respect to the d-dimensional Lebesgue measure), the problem is much more difficult. We present a counter example of a not locally contractible set, which is r-convex. This also proves that the class of supports with positive reach of absolutely continuous distributions includes strictly the class of r-convex supports of absolutely continuous distributions.ANII: FCE_1_2019_1_156054Universitat Politècnica de ValènciaCholaquidis Alejandro, Universidad de la República (Uruguay). Facultad de Ciencias. Centro de Matemática.2023-06-02T14:26:16Z2023-06-02T14:26:16Z2023Artículoinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersion4 happlication/pdfCholaquidis, A. " A counter example on a Borsuk conjecture". Applied General Topology. [en línea] 2023, 24(1): 125-128. 4 h.1989-4147https://hdl.handle.net/20.500.12008/3737410.4995/agt.2023.18176reponame:COLIBRIinstname:Universidad de la Repúblicainstacron:Universidad de la RepúblicaenengApplied General Topology, 2023, 24(1): 125-128Las obras depositadas en el Repositorio se rigen por la Ordenanza de los Derechos de la Propiedad Intelectual de la Universidad de la República.(Res. Nº 91 de C.D.C. de 8/III/1994 – D.O. 7/IV/1994) y por la Ordenanza del Repositorio Abierto de la Universidad de la República (Res. Nº 16 de C.D.C. de 07/10/2014)info:eu-repo/semantics/openAccessLicencia Creative Commons Atribución - No Comercial - Sin Derivadas (CC - By-NC-ND 4.0)oai:colibri.udelar.edu.uy:20.500.12008/373742026-04-14T10:10:05Z
spellingShingle A counter example on a Borsuk conjecture
Cholaquidis, Alejandro
r-convex set
Locally contractible set
Positive reach
status_str publishedVersion
title A counter example on a Borsuk conjecture
title_full A counter example on a Borsuk conjecture
title_fullStr A counter example on a Borsuk conjecture
title_full_unstemmed A counter example on a Borsuk conjecture
title_short A counter example on a Borsuk conjecture
title_sort A counter example on a Borsuk conjecture
topic r-convex set
Locally contractible set
Positive reach
url https://hdl.handle.net/20.500.12008/37374