Density of a final segment of the truth-table degrees

Jean-Leah Mohrherr
1984 Pacific Journal of Mathematics  
This work answers two questions from the topic of degrees of unsolvability, which is part of recursive function theory. We give a simple and explicit example of elementary inequivalence of the Turing degrees to the truth-table degrees. In constructing this example, we show that every truth-table degree above that of the halting problem is the jump of another truth-table degree.
doi:10.2140/pjm.1984.115.409 fatcat:h2pewm3ddvfcdivrhpb4djjpgm