Hostname: page-component-586b7cd67f-tf8b9 Total loading time: 0 Render date: 2024-11-30T20:25:26.116Z Has data issue: false hasContentIssue false

On the weak non-finite cover property and the n-tuples of simple structures

Published online by Cambridge University Press:  12 March 2014

Evgueni Vassiliev*
Affiliation:
Wilkes Honors College, Florida Atlantic University, 5353 Parkside Drive, Jupiter, Florida 33458, USA, E-mail: [email protected]

Abstract

The weak non-finite cover property (wnfcp) was introduced in [1] in connection with “axiomatizability” of lovely pairs of models of a simple theory. We find a combinatorial condition on a simple theory equivalent to the wnfcp, yielding a direct proof that the non-finite cover property implies the wnfcp, and that the wnfcp is preserved under reducts. We also study the question whether the wnfcp is preserved when passing from a simple theory T to the theory Tp of lovely pairs of models of T (true in the stable case). While the question remains open, we show, among other things, that if (for a T with the wnfcp) Tp is low, then TP has the wnfcp. To study this question, we describe “double lovely pairs”, and, along the way, we develop the notion of a “lovely n-tuple” of models of a simple theory, which is an analogue of the notion of a beautiful tuple of models of stable theories [2].

Type
Research Article
Copyright
Copyright © Association for Symbolic Logic 2005

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

[1]Ben-Yaacov, I., Pillay, A., and Vassiliev, E., Lovely pairs of models, Annals of Pure and Applied Logic, vol. 122 (2003), pp. 235261.CrossRefGoogle Scholar
[2]Bouscaren, E. and Poizat, B., Des belles paires aux beaux uples, this Journal, vol. 53 (1988), pp. 434442.Google Scholar
[3]Pillay, A., On countable simple unidimensional theories, this Journal, vol. 68 (2003), no. 4, pp. 13771384.Google Scholar
[4]Poizat, B., Paires de structures stables, this Journal, vol. 48 (1983), pp. 234249.Google Scholar
[5]Shami, Z., Coordinatization by binding groups and unidimensionality in simple theories, this Journal, vol. 69 (2004), pp. 12211242.Google Scholar
[6]Shelah, S., Classification theory, North Holland, Amsterdam, 1990.Google Scholar
[7]Vassiliev, E., Generic pairs of SU-rank 1 structures, Annals of Pure and Applied Logic, vol. 120 (2003), pp. 103149.CrossRefGoogle Scholar