[FOM] CFR and Programme: SoTFoM III and The Hyperuniverse Programme, Vienna, 21-23 September 2015.

katzmik at macs.biu.ac.il katzmik at macs.biu.ac.il
Thu Aug 27 12:47:46 EDT 2015

This is an error, Harvey.  A definable model of the hyperreals was constructed
by Kanovei and Shelah in

Kanovei, Vladimir; Shelah, Saharon A definable nonstandard model of the reals.
J. Symbolic Logic  69  (2004),  no. 1, 159–164.


On Thu, August 27, 2015 08:12, Harvey Friedman wrote:
> 4. `Non-standard analysis as a computational foundation.'
> Alternative foundational schemes with some systematic robust idea is
> always red meat. An interesting feature of non standardism is both its
> drawbacks and its successes. On the drawback side, we know that there
> cannot be any preferred or even describable model of nonstandard
> analysis in various senses. There is probably more to do along this
> negative vein than has been done. The most well known is that there is
> no formula which, provably in ZFC, defines a particular example of
> various particular kinds of nonstandard models.

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