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Nondiversity in substructures

Published online by Cambridge University Press:  12 March 2014

James H. Schmerl*
Affiliation:
Department of Mathematics, University of Connecticut, Storrs, Connecticut 06269, USA, E-mail: schmerl@math.uconn.edu

Abstract

For a model of Peano Arithmetic, let Lt() be the lattice of its elementary substructures, and let Lt+ () be the equivalenced lattice (Lt(),≅), where ≅ is the equivalence relation of isomorphism on Lt(). It is known that Lt+() is always a reasonable equivalenced lattice.

Theorem. Let L be a finite distributive lattice and let (L, E) be reasonable. If 0 is a nonstandard prime model of PA, then 0 has a cofinal extension such that Lt+() ≅ (L,E).

A general method for proving such theorems is developed which, hopefully, will be able to be applied to some nondistributive lattices.

Type
Research Article
Copyright
Copyright © Association for Symbolic Logic 2008

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References

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