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From: Toby Bartels <toby@math.ucr.edu>
To: categories@mta.ca
Subject: Re: What does it take to identify the field and the continuum of reals?
Date: Sun, 26 Jan 2003 15:25:37 -0800	[thread overview]
Message-ID: <20030126232537.GB9502@math-lw-n06.ucr.edu> (raw)
In-Reply-To: <200301252120.NAA26529@coraki.Stanford.EDU>

Vaughan Pratt wrote in part:

[about Conway's surreal numbers]

>Now I conjecture that stopping just before day \epsilon_0, for the sake of
>getting a set, produces a field closed under all functions whose n-th bit is
>computable in time f(n) where f is definable in Peano arithmetic.  And it
>may well be that Conway already has a field just before day \omega^\omega,
>I haven't checked but surely someone has by now (I'm very bad at keeping
>up with these things, sorry).

It's my understanding that you don't get a field until
(just before) day K for K an inaccessible cardinal number.
I'm not 100% certain about this, however!


-- Toby Bartels





  reply	other threads:[~2003-01-26 23:25 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-01-25 21:20 Vaughan Pratt
2003-01-26 23:25 ` Toby Bartels [this message]
2003-01-27 11:50 ` Martin Escardo

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