On Discrete Borel Spaces and Projective Sets
نویسنده
چکیده
Let J denote the unit interval, S—IXI the unit square; Cj and Cs the class of all subsets of I and 6, respectively. By Cj X Cj is meant the or-algebra on S generated by rectangles with sides in C/. The purpose of this note is to prove the following theorem (which settles a problem of S. M. Ulam) and observe some of its consequences. Without explicit mention, the axiom of choice has been assumed throughout this paper. CH stands for the continuum hypothesis.
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تاریخ انتشار 2007