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Stationary sets and infinitary logic

Published online by Cambridge University Press:  12 March 2014

Saharon Shelah
Affiliation:
Institute of Mathematics, Hebrew University, Jerusalem, Israel
Jouko Väänänen
Affiliation:
Department of Mathematics, University of Helsinki, Helsinki, Finland

Abstract

Let be the class of structures 〈λ, <, A〉, where Aλ is disjoint from a club, and let be the class of structures 〈λ, <, A), where Aλ contains a club. We prove that if λ = λ<κ is regular, then no sentence of Lλ + κ separates and On the other hand, we prove that if λ = μ+ , μ = μ<μ, and a forcing axiom holds (and if μ = ℵ0), then there is a sentence of Lλλ which separates and .

Type
Research Article
Copyright
Copyright © Association for Symbolic Logic 2000

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References

REFERENCES

[1]Hyttinen, T., Model theory for infinite quantifier languages, Fundamenta Mathematicae, vol. 134 (1990), pp. 125–142.CrossRefGoogle Scholar
[2]Martin, D. A. and Solovay, R. M., Internal Cohen extensions, Annals of Mathematical Logic, vol. 2 (1970), no. 2, pp. 143–178.CrossRefGoogle Scholar
[3]Mekler, A. and Shelah, S., The Canary tree, Canadian Mathematical Bulletin, vol. 36 (1993), no. 2, pp. 209–215.CrossRefGoogle Scholar
[4]Mekler, A. and Väänänen, J., Trees and -subsets of ω1ω1, This Journal, vol. 58 (1993), pp. 1052–1070.Google Scholar
[5]Shelah, S., A weak generalization of MA to higher cardinals, Israel Journal of Mathematics, vol. 30 (1978), pp. 297–306.CrossRefGoogle Scholar
[6]Todorčević, S. and Väänänen, J., Trees and Ehrenfeucht-Fraïssé games, Annals of Pure and Applied Logic, vol. 100 (1999), pp. 69–97.CrossRefGoogle Scholar