On computable automorphisms of the rational numbers
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AbstractThe relationship between ideals I of Turing degrees and groups of I-recursive automorphisms of the ordering on rationals is studied. We discuss the differences between such groups and the group of all automorphisms, prove that the isomorphism type of such a group completely defines the ideal I, and outline a general correspondence between principal ideals of Turing degrees and the first-order properties of such groups.
1996 ◽
Vol 10
(05)
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pp. 561-572
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1997 ◽
Vol 36
(04/05)
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pp. 315-318
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2012 ◽
Vol 12
(01)
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pp. 1250005
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