[FOM] Countable sets with imprediicative definitions

[Monroe Eskew]

It is consistent that every set has a predicative definition with
parameters.  V=L implies this.

Monroe

On Thu, Nov 18, 2010 at 2:58 AM, Margaret MacDougall
<Margaret.MacDougall at ed.ac.uk> wrote:
> Can anyone provide examples of countable sets with impredicative
> definitions and apparently no alternative predicative definitions? Just
> to clarify, my intended notion of countable in relation to a set refers
> to the existence of a surjection from the natural numbers (or from the
> natural numbers excluding zero) to that set.
>
>
> --
> The University of Edinburgh is a charitable body, registered in
> Scotland, with registration number SC005336.
>
> _______________________________________________
> FOM mailing list
> FOM at cs.nyu.edu
> http://www.cs.nyu.edu/mailman/listinfo/fom
>