Structures having o-minimal open core

Authors:
Alfred Dolich, Chris Miller and Charles Steinhorn

Journal:
Trans. Amer. Math. Soc. **362** (2010), 1371-1411

MSC (2000):
Primary 03C64; Secondary 06F20

Published electronically:
October 8, 2009

MathSciNet review:
2563733

Full-text PDF Free Access

Abstract | References | Similar Articles | Additional Information

Abstract: The open core of an expansion of a dense linear order is its reduct, in the sense of definability, generated by the collection of all of its open definable sets. In this paper, expansions of dense linear orders that have o-minimal open core are investigated, with emphasis on expansions of densely ordered groups. The first main result establishes conditions under which an expansion of a densely ordered group has an o-minimal open core. Specifically, the following is proved:

Two examples of classes of structures that are not o-minimal yet have o-minimal open core are discussed: dense pairs of o-minimal expansions of ordered groups, and expansions of o-minimal structures by generic predicates. In particular, such structures have open core interdefinable with the original o-minimal structure. These examples are differentiated by the existence of definable unary functions whose graphs are dense in the plane, a phenomenon that can occur in dense pairs but not in expansions by generic predicates. The property of having no dense graphs is examined and related to uniform finiteness, definable completeness, and having o-minimal open core.Let be an expansion of a densely ordered group that is definably complete and satisfies the uniform finiteness property. Then the open core of is o-minimal.

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Additional Information

**Alfred Dolich**

Affiliation:
Department of Mathematics and Computer Science, Chicago State University, Chicago, Illinois 60628

Address at time of publication:
Department of Mathematics, East Stroudsberg University, East Stroudsberg, Pennsylvania 18301

Email:
adolich@csu.edu

**Chris Miller**

Affiliation:
Department of Mathematics, 231 West 18th Avenue, The Ohio State University, Columbus, Ohio 43210

Email:
miller@math.ohio-state.edu

**Charles Steinhorn**

Affiliation:
Department of Mathematics, Vassar College, Poughkeepsie, New York 12604

Email:
steinhorn@vassar.edu

DOI:
https://doi.org/10.1090/S0002-9947-09-04908-3

Keywords:
o-minimal,
open core,
ordered group,
ordered field,
uniform finiteness,
definably complete,
exchange property,
definable Skolem functions,
elimination of imaginaries,
independence property,
atomic model,
dense pair,
generic predicate,
tame pair

Received by editor(s):
January 7, 2008

Published electronically:
October 8, 2009

Additional Notes:
The second author was partially supported by NSF Grant DMS-9988855. The third author was partially supported by NSF Grant DMS-0070743.

Article copyright:
© Copyright 2009
American Mathematical Society