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Ɗ-MAXIMAL SETS
Soare [20] proved that the maximal sets form an orbit in ε. We consider here Ɗ-maximal sets, generalizations of maximal sets introduced by Herrmann and Kummer [12]. Some orbits of Ɗ-maximal sets are well understood, e.g., hemimaximal sets [8], but many are not. The goal of this paper is to define ne...
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Published in: | The Journal of symbolic logic 2015-12, Vol.80 (4), p.1182-1210 |
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Main Authors: | , , |
Format: | Article |
Language: | English |
Subjects: | |
Online Access: | Get full text |
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Summary: | Soare [20] proved that the maximal sets form an orbit in ε. We consider here Ɗ-maximal sets, generalizations of maximal sets introduced by Herrmann and Kummer [12]. Some orbits of Ɗ-maximal sets are well understood, e.g., hemimaximal sets [8], but many are not. The goal of this paper is to define new invariants on computably enumerable sets and to use them to give a complete nontrivial classification of the Ɗ-maximal sets. Although these invariants help us to better understand the Ɗ-maximal sets, we use them to show that several classes of Ɗ-maximal sets break into infinitely many orbits. |
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ISSN: | 0022-4812 1943-5886 |
DOI: | 10.1017/jsl.2015.3 |