Abstract of a paper by Carlo Alberto De Bernardi, Jacopo Somaglia, Libor Vesely
This is an announcement for the paper “Star-finite coverings of Banach spaces” by Carlo Alberto De Bernardi<https://arxiv.org/search/math?searchtype=author&query=De+Bernardi%2C+C+A>, Jacopo Somaglia<https://arxiv.org/search/math?searchtype=author&query=Somaglia%2C+J>, Libor Vesely<https://arxiv.org/search/math?searchtype=author&query=Vesely%2C+L>. Abstract: We study star-finite coverings of infinite-dimensional normed spaces. A family of sets is called star-finite if each of its members intersects only finitely many other members of the family. It follows by our results that an LUR or a uniformly Fréchet smooth infinite-dimensional Banach space does not admit star-finite coverings by closed balls. On the other hand, we present a quite involved construction proving existence of a star-finite covering of $c_0(\Gamma)$ by Fréchet smooth centrally symmetric bounded convex bodies. A similar but simpler construction shows that every normed space of countable dimension (and hence incomplete) has a star-finite covering by closed balls. The paper may be downloaded from the archive by web browser from URL https://arxiv.org/abs/2002.04308
participants (1)
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Bentuo Zheng (bzheng)