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A dedekind finite borel set
Authors:Arnold W Miller
Institution:1. Department of Mathematics, University of Wisconsin-Madison, Van Vleck Hall, 480 Lincoln Drive, Madison, WI, 53706-1388, USA
Abstract:In this paper we prove three theorems about the theory of Borel sets in models of ZF without any form of the axiom of choice. We prove that if ${B\subseteq 2^\omega}$ is a G ??? -set then either B is countable or B contains a perfect subset. Second, we prove that if 2 ?? is the countable union of countable sets, then there exists an F ??? set ${C\subseteq 2^\omega}$ such that C is uncountable but contains no perfect subset. Finally, we construct a model of ZF in which we have an infinite Dedekind finite ${D\subseteq 2^\omega}$ which is F ??? .
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