[FOM] Banach spaces: A more precise question
Timothy Y. Chow
tchow at alum.mit.edu
Tue Feb 17 16:20:18 EST 2009
I wrote:
> This is a followup to my previous vague inquiry about Banach spaces.
> Can the existence of Tsirelson's space be proved in RCA_0?
Because of interest in this question, Gowers has started a new blog entry
for it.
http://tinyurl.com/banach2
Let me mention that one reason to suspect that the existence of
Tsirelson's space may not be provable in RCA_0 is that according to
Gowers, the usual definition involves an induction over a set of finite
trees, which has a bit of the feeling of the weak Koenig lemma to it.
This could turn into quite an interesting application of reverse
mathematics if it pans out.
Tim
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