论文信息 - The members of thin and minimal classes, their ranks and Turing degrees

The members of thin and minimal classes, their ranks and Turing degrees

Abstract We study the relationship among members of Π 1 0 classes, thin Π 1 0 classes, their Cantor–Bendixson ranks and their Turing degrees; in particular, we show that any nonzero Δ 2 0 degree contains a member of rank α for any computable ordinal α. Furthermore we observe that the degrees containing members of thin Π 1 0 classes are not closed under join.

Guohua Wu | Yue Yang | Rodney G. Downey

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