Steinhaus' lattice-point problem for Banach spaces

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• 作者：Tomasz Kania^a ; ^b ; ^{tomasz.marcin.kania@gmail.com" class="auth_mail" title="E-mail the corresponding author} ; ^{t.kania@warwick.ac.uk" class="auth_mail" title="E-mail the corresponding author} ; Tomasz Kochanek^c ; ^d ; ^{tkoch@impan.pl" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Steinhaus' problem ; Lattice points ; Strictly convex space
• 刊名：Journal of Mathematical Analysis and Applications
• 出版年：2017
• 出版时间：15 February 2017
• 年：2017
• 卷：446
• 期：2
• 页码：1219-1229
• 全文大小：481 K

文摘

Steinhaus proved that given a positive integer n, one may find a circle surrounding exactly n points of the integer lattice. This statement has been recently extended to Hilbert spaces by Zwoleński, who replaced the integer lattice by any infinite set that intersects every ball in at most finitely many points. We investigate Banach spaces satisfying this property, which we call (S), and characterise them by means of a new geometric property of the unit sphere which allows us to show, e.g., that all strictly convex norms have (S), nonetheless, there are plenty of non-strictly convex norms satisfying (S). We also study the corresponding renorming problem.