The degrees of hyperhyperimmune sets
- 17 November 1969
- journal article
- Published by Cambridge University Press (CUP) in The Journal of Symbolic Logic
- Vol. 34 (3) , 489-493
- https://doi.org/10.2307/2270912
Abstract
In [5, Corollary 3.1] D. A. Martin characterized the degrees of the hyperhypersimple sets as those r.e. degrees a satisfying a′ = 0″. In the present paper we investigate the degrees of the hyperhyperimmune (h.h.i.) sets. We do not achieve a characterization of these degrees, but we do show that the condition a′ ≥ 0″ is sufficient, and the condition a′ ≥ 0′ is necessary, for a degree a to contain an h.h.i. set.Keywords
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