The notion of point of local nonconvexity has been an important tool in the study of the geometry of nonconvex sets, since Tietze characterized, more than fifty years ago, the convex subsets of En as those connected sets without points of local nonconvexity. It is proved here that for each convex component K of a closed connected set S in a locally convex space there exist points of local nonconvexity of S arbitrarily close to K, unless S itself be convex. Klee’s generalization of the just quoted Tietze’s theorem follows immediately. The notion of “higher visibility” is introduced in the last section, and three Erasnosselsky-type theorems involving the points of local nonconvexity are proved. © 1982, University of California, Berkeley. All Rights Reserved.
Documento: | Artículo |
Título: | The points of local nonconvexity of starshaped sets |
Autor: | Toranzos, F.A. |
Filiación: | Facultad De Ciencias Exactas Y Naturales, Universidad De Buenos Aires, Koganei-Shi, Buenos Aires, Argentina |
Año: | 1982 |
Volumen: | 101 |
Número: | 1 |
Página de inicio: | 209 |
Página de fin: | 213 |
DOI: | http://dx.doi.org/10.2140/pjm.1982.101.209 |
Título revista: | Pacific Journal of Mathematics |
Título revista abreviado: | Pac. J. Math. |
ISSN: | 00308730 |
Registro: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00308730_v101_n1_p209_Toranzos |