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REDUCTS OF STRUCTURES AND MAXIMAL-CLOSED PERMUTATION GROUPS

Published online by Cambridge University Press:  14 September 2016

MANUEL BODIRSKY
Affiliation:
INSTITUT FÜR ALGEBRA TU DRESDEN 01062 DRESDEN GERMANYE-mail:[email protected]
DUGALD MACPHERSON
Affiliation:
SCHOOL OF MATHEMATICS UNIVERSITY OF LEEDS LEEDS LS2 9JT, UKE-mail: [email protected]

Abstract

Answering a question of Junker and Ziegler, we construct a countable first order structure which is not ω-categorical, but does not have any proper nontrivial reducts, in either of two senses (model-theoretic, and group-theoretic). We also construct a strongly minimal set which is not ω-categorical but has no proper nontrivial reducts in the model-theoretic sense.

Type
Articles
Copyright
Copyright © The Association for Symbolic Logic 2016 

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