Notre Dame Journal of Formal Logic

The Decidability of the $ \forall^*\exists$ Class and the Axiom of Foundation

Dorella Bellè and Franco Parlamento
Source: Notre Dame J. Formal Logic Volume 42, Number 1 (2001), 41-53.

Abstract

We show that the Axiom of Foundation, as well as the Antifoundation Axiom AFA, plays a crucial role in determining the decidability of the following problem. Given a first-order theory T over the language $ =,\in$, and a sentence F of the form $ \forall x_1, \ldots, x_n \exists y F^M$ with $ F^M$ quantifier-free in the same language, are there models of T in which F is true? Furthermore we show that the Extensionality Axiom is quite irrelevant in that respect.

First Page: Show Hide
Primary Subjects: 03B25, 03C62
Secondary Subjects: 03E50
Links and Identifiers

Permanent link to this document: http://projecteuclid.org/euclid.ndjfl/1054301354
Digital Object Identifier: doi:10.1305/ndjfl/1054301354
Mathematical Reviews number (MathSciNet): MR1993389
Zentralblatt MATH identifier: 1023.03007

References

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Digital Object Identifier: doi:10.1305/ndjfl/1040248461
Project Euclid: euclid.ndjfl/1040248461
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Mathematical Reviews (MathSciNet): MR97d:04003
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Digital Object Identifier: doi:10.1090/S0002-9939-97-03630-7
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Mathematical Reviews (MathSciNet): MR93a:03052
Zentralblatt MATH: 0744.03051

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Notre Dame Journal of Formal Logic

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