The Journal of Symbolic Logic

Research Article

Wtt-degrees and T-degrees of r.e. sets

Michael Stob  1

Massachusetts Institute of Technology, Cambridge, Massachusetts 02139

Abstract

We use some simple facts about the wtt-degrees of r.e. sets together with a construction to answer some questions concerning the join and meet operators in the r.e. degrees. The construction is that of an r.e. Turing degree a with just one wtt-degree in a such that a is the join of a minimal pair of r.e. degrees. We hope to illustrate the usefulness of studying the stronger reducibility orderings of r.e. sets for providing information about Turing reducibility.

(Received May 29 1981)

Correspondence

Calvin College, Grand Rapids, Michigan 49506

Footnotes

1   This research was supported by NSF Grant MCS 80-02937. The results were presented to the 1981 Spring Meeting of the A.S.L. at Milwaukee.