2001/09/23 by Lorenz Halbeisen
Mathematics · #math.LO #msc:46B20 #msc:54E52
published as Colloquium Mathematicum 89 (2001) 133-134
arxiv created 2001/09/23 · arxiv updated 2009/11/30
We call a subset S of a topological vector space V linearly Borel, if for every finite number n, the set of all linear combinations of S of length n is a Borel subset of V. It will be shown that a Hamel base of an infinite dimensional Banach space can never be linearly Borel. This answers a question of Anatolij Plichko.