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THE NUMBER OF ATOMIC MODELS OF UNCOUNTABLE THEORIES

Published online by Cambridge University Press:  08 February 2018

DOUGLAS ULRICH*
Affiliation:
DEPARTMENT OF MATHEMATICS UNIVERSITY OF MARYLAND COLLEGE PARK MD, USAE-mail:[email protected]

Abstract

We show there exists a complete theory in a language of size continuum possessing a unique atomic model which is not constructible. We also show it is consistent with $ZFC + {\aleph _1} < {2^{{\aleph _0}}}$ that there is a complete theory in a language of size ${\aleph _1}$ possessing a unique atomic model which is not constructible. Finally we show it is consistent with $ZFC + {\aleph _1} < {2^{{\aleph _0}}}$ that for every complete theory T in a language of size ${\aleph _1}$, if T has uncountable atomic models but no constructible models, then T has ${2^{{\aleph _1}}}$ atomic models of size ${\aleph _1}$.

Type
Articles
Copyright
Copyright © The Association for Symbolic Logic 2018 

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References

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