Model-theoretic complexity of automatic structures

We study the complexity of automatic structures via well-established concepts from both logic and model theory, including ordinal heights (of well-founded relations), Scott ranks of structures, and Cantor–Bendixson ranks (of trees). We prove the following results: (1) The ordinal height of any autom...

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Main Authors: Khoussainov, Bakhadyr, Minnes, Mia
Other Authors: Massachusetts Institute of Technology. Department of Mathematics
Format: Article
Language:en_US
Published: Elsevier 2015
Online Access:http://hdl.handle.net/1721.1/96326
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author Khoussainov, Bakhadyr
Minnes, Mia
author2 Massachusetts Institute of Technology. Department of Mathematics
author_facet Massachusetts Institute of Technology. Department of Mathematics
Khoussainov, Bakhadyr
Minnes, Mia
author_sort Khoussainov, Bakhadyr
collection MIT
description We study the complexity of automatic structures via well-established concepts from both logic and model theory, including ordinal heights (of well-founded relations), Scott ranks of structures, and Cantor–Bendixson ranks (of trees). We prove the following results: (1) The ordinal height of any automatic well-founded partial order is bounded by ω[superscript ω]. (2) The ordinal heights of automatic well-founded relations are unbounded below ω[subscript 1 superscript CK], the first non-computable ordinal. (3) For any computable ordinal α, there is an automatic structure of Scott rank at least αα. Moreover, there are automatic structures of Scott rank ω[subscript 1 superscript CK],ω[subscript 1 superscript CK] +1. (4) For any computable ordinal α, there is an automatic successor tree of Cantor–Bendixson rank α.
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spelling mit-1721.1/963262022-09-29T21:00:20Z Model-theoretic complexity of automatic structures Khoussainov, Bakhadyr Minnes, Mia Massachusetts Institute of Technology. Department of Mathematics Minnes, Mia We study the complexity of automatic structures via well-established concepts from both logic and model theory, including ordinal heights (of well-founded relations), Scott ranks of structures, and Cantor–Bendixson ranks (of trees). We prove the following results: (1) The ordinal height of any automatic well-founded partial order is bounded by ω[superscript ω]. (2) The ordinal heights of automatic well-founded relations are unbounded below ω[subscript 1 superscript CK], the first non-computable ordinal. (3) For any computable ordinal α, there is an automatic structure of Scott rank at least αα. Moreover, there are automatic structures of Scott rank ω[subscript 1 superscript CK],ω[subscript 1 superscript CK] +1. (4) For any computable ordinal α, there is an automatic successor tree of Cantor–Bendixson rank α. Marsden Fund 2015-04-02T16:00:24Z 2015-04-02T16:00:24Z 2009-08 Article http://purl.org/eprint/type/JournalArticle 01680072 http://hdl.handle.net/1721.1/96326 Khoussainov, Bakhadyr, and Mia Minnes. “Model-Theoretic Complexity of Automatic Structures.” Annals of Pure and Applied Logic 161, no. 3 (December 2009): 416–426. © 2009 Elsevier B.V. en_US http://dx.doi.org/10.1016/j.apal.2009.07.012 Annals of Pure and Applied Logic Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf Elsevier Elsevier
spellingShingle Khoussainov, Bakhadyr
Minnes, Mia
Model-theoretic complexity of automatic structures
title Model-theoretic complexity of automatic structures
title_full Model-theoretic complexity of automatic structures
title_fullStr Model-theoretic complexity of automatic structures
title_full_unstemmed Model-theoretic complexity of automatic structures
title_short Model-theoretic complexity of automatic structures
title_sort model theoretic complexity of automatic structures
url http://hdl.handle.net/1721.1/96326
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