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Model companions for finitely generated universal Horn classes

Published online by Cambridge University Press:  12 March 2014

Stanley Burris*
Affiliation:
University of Waterloo, Waterloo, Ontario, Canada N2L 3G1

Abstract

In an earlier paper we proved that a universal Horn class generated by finitely many finite structures has a model companion. If the language has only finitely many fundamental operations then the theory of the model companion admits a primitive recursive elimination of quantifiers and is primitive recursive. The theory of the model companion is ℵ0-categorical iff it is complete iff the universal Horn class has the joint embedding property iff the universal Horn class is generated by a single finite structure. In the last section we look at structure theorems for the model companions of universal Horn classes generated by functionally complete algebras, in particular for the cases of rings and groups.

Type
Research Article
Copyright
Copyright © Association for Symbolic Logic 1984

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References

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