Submission date: 4 September 2014.

Abstract:

The goal of this paper is to generalise Alex Rennet's proof of the non-axiomatizability of the class of pseudo-o-minimal structures. Rennet showed that if L is an expansion of the language of ordered fields and K is the class of pseudo-o-minimal L-structures (L-structures elementarily equivalent to an ultraproduct of o-minimal structures) then K is not axiomatizable.

Mathematics Subject Classification: 03C20

Keywords and phrases:

Full text arXiv 1409.1608: pdf, ps.