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Vestnik Novosibirskogo Gosudarstvennogo Universiteta. Seriya Matematika, Mekhanika, Informatika, 2007, Volume 7, Issue 3, Pages 13–44
(Mi vngu265)
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Conservative extensions of models with weakly o-minimal theories
B. S. Baizhanov Institute for Problems of Informatics and Control Sciences, Almaty
Abstract:
Let M≺N. It is said that a pair of models (M,N) is conservative pair and N is conservative extension of M if for any finite tuple of elements ¯α from N, tp(¯α|M) is definable. We say that elementary extension N of M is D-good if any definable q∈S(M∪¯α) (¯α∈N∖M) is realized in N and N is CD-good if any non-isolated one-type q∈S1(M∪¯α) (¯α∈N∖M), which is determined (approximated) by definable ϕ-type, is realized in N.
We prove that any model M of any weakly o-minimal theory except one, theory of discrete order with ends, has conservative extension. The central point in our paper is the criterion of the existence of the CD-ω-saturated conservative extension of an arbitrary model of weakly o-minimal theory (Theorem 2). As corollary of this proof it follows the existence of CD-ω-saturated conservative extension for any model of any weakly o-minimal theory except one and the results on omitting of natural family of definable one-types and all non-definable types (Corollary 5). The existence of conservative and CD-ω-saturated conservative extensions for o-minimal theories have been proved accordingly in D. Marker, “Omitting types in o-minimal theories”, The Journal of Symbolic Logic, Vol. 51(1986), P. 63–74., Y. Baisalov, B. Poizat, “Paires de structures o-minimales”, The Journal of Symbolic Logic, Vol. 63(1998), P. 570–578.
Received: 30.04.2003
Citation:
B. S. Baizhanov, “Conservative extensions of models with weakly o-minimal theories”, Vestn. Novosib. Gos. Univ., Ser. Mat. Mekh. Inform., 7:3 (2007), 13–44
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https://www.mathnet.ru/eng/vngu265 https://www.mathnet.ru/eng/vngu/v7/i3/p13
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Abstract page: | 264 | Full-text PDF : | 99 | References: | 70 | First page: | 1 |
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