dc.contributor.author Downey, Rod dc.contributor.author Melnikov, Alexander dc.contributor.author Ng, Keng Meng dc.date.accessioned 2018-04-26T09:23:09Z dc.date.available 2018-04-26T09:23:09Z dc.date.issued 2018-04-26 dc.identifier.uri http://publications.mfo.de/handle/mfo/1361 dc.description.abstract We prove that for every computable limit ordinal $\alpha$ there exists a computable linear ordering $\mathcal{A}$ which is $\Delta^0_\alpha$-categorical and $\alpha$ is smallest such, but nonetheless for every isomorphic computable copy $\mathcal{B}$ of $\mathcal{A}$ there exists a $\beta< \alpha$ such that $\mathcal{A} \cong_{\Delta^0_\beta} \mathcal{B}$. This answers a question left open in the earlier work of Downey, Igusa, and Melnikov. We also show that such examples can be found among ordered abelian groups and real-closed fields. en_US dc.language.iso en_US en_US dc.publisher Mathematisches Forschungsinstitut Oberwolfach en_US dc.relation.ispartofseries Oberwolfach Preprints;2018,08 dc.title Categorical Linearly Ordered Structures en_US dc.type Preprint en_US dc.identifier.doi 10.14760/OWP-2018-08 local.scientificprogram Research in Pairs 2018 en_US local.series.id OWP-2018-08 en_US local.subject.msc 03 en_US
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