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Kelley 1.T, Brouwer reduction theorem

Subject: Kelley 1.T, Brouwer reduction theorem
From: "Stephen J. Herschkorn"
Date: Sat, 30 Sep 2006 00:12:12 -0400
Newsgroups: sci.math
Problem 1.T in Kelley basically asks the reader to prove the following version of the Brouwer Reduction Theorem. Consider a topological space all of whose subspaces are Lindeloef. Let C be a collection of closed sets with the property that if D is a countable chain (with respect to inclusion) and a subfamily of C, then the intersection of D is in C. Then for any A in C, there exists a minimal susbset B of A which is also in C.

First question: My proof invokes Zorn's lemma. Have I relied on the Axiom of Choice unnecessarily?

1.T(b) asks, in "an arbritrary topological space can any result of this general sort be affirmed?" My answer is that one should remove the countable condition on D from the above hypothesis. Is there a less restrictive hypothesis for this "sort" of result?

[BTW, this is not HW.]

--
Stephen J. Herschkorn                        sjherschko@xxxxxxxxxxxx
Math Tutor on the Internet and in Central New Jersey and Manhattan


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