Posted by: Alexandre Borovik | December 28, 2008

## Consitent group choice and ultrafilters

Since I first encountered ultraproduct I had a feeling that Łoś’s theorem is a kind of a voting scheme on the set of indices $I$ in the ultraproduct $\prod_{i\in I} M_i/\mathcal{U}.$ This happened to be a relatively well known interpretation, developed mostly in the theory of social choice.  Still, I felt that it is worthwhile to document a clean mathematical treatment of the issue, which I did in this preprint.