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Rich models

Published online by Cambridge University Press:  12 March 2014

Michael H. Albert
Affiliation:
Department of Mathematics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213
Rami P. Grossberg
Affiliation:
Department of Mathematics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213

Abstract

We define a rich model to be one which contains a proper elementary substructure isomorphic to itself. Existence, nonstructure, and categoricity theorems for rich models are proved. A theory T which has fewer than min(2λ, ℶ2) rich models of cardinality λ (λ > ∣T∣) is totally transcendental. We show that a countable theory with a unique rich model in some uncountable cardinal is categorical in ℵ1 and also has a unique countable rich model. We also consider a stronger notion of richness, and use it to characterize superstable theories.

Type
Research Article
Copyright
Copyright © Association for Symbolic Logic 1990

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References

REFERENCES

[1]Baldwin, J. T., The spectrum of resplendency, this Journal, vol. 55 (1990), pp. 626636.Google Scholar
[2]Buechler, Steven, Resplendency and recursive definability in ω-stable theories, Israel Journal of Mathematics, vol. 49 (1984), pp. 2633.CrossRefGoogle Scholar
[3]Shelah, Saharon, The lazy model-theoretician's guide to stability theory, Logique et Analyse (Nouvelle Série), vol. 18 (1975), pp. 241308.Google Scholar
[4]Shelah, Saharon, Classification of non-elementary classes. II, Classification theory (proceedings, Chicago, 1985, Baldwin, J. T., editor), Lecture Notes in Mathematics, vol. 1292, Springer-Verlag, Berlin, 1987, pp. 419497.Google Scholar
[5]Shelah, Saharon, Thenumber of pairwise non-elementarily-embeddable models, this Journal, vol. 54 (1989), pp. 14311456.Google Scholar
[6]Shelah, Saharon, Classification theory and the number of non-isomorphic models, 2nd ed., North-Holland, Amsterdam (to appear).Google Scholar