On the typical structure of compact sets

Citation
J. Myjak et R. Rudnicki, On the typical structure of compact sets, ARCH MATH, 76(2), 2001, pp. 119-126
Citations number
15
Categorie Soggetti
Mathematics
Journal title
ARCHIV DER MATHEMATIK
ISSN journal
0003889X → ACNP
Volume
76
Issue
2
Year of publication
2001
Pages
119 - 126
Database
ISI
SICI code
0003-889X(20010201)76:2<119:OTTSOC>2.0.ZU;2-V
Abstract
Let E be a strictly convex separable Banach space of dimension at least 2. A compact set K subset of E has hispid structure if the nearest point mappi ng p(K) : E --> 2(K) is not single valued on a dense subset of E. It is pro ved that if K is a union of disjoint compact sets K-1, K-2 and K has hispid structure, then K-1 and K-2 have hispid structure. Furthermore. it is show n that for typical tin the sense of Baire category) compact set K and arbit rary x is an element of E the set of all r > 0 such that the intersection K boolean AND B(x, r) not equal 0 and has no hispid structure is of Jordan m easure zero.