Initial segments of the degrees of unsolvability Part II: minimal degrees
C. E. M. Yates · Journal of Symbolic Logic · 1970
The first of this sequence of papers [21] surveyed the progress that has been made in embedding partially ordered sets as initial segments of the uncountable upper semilattice D of degrees of unsolvability. The principal concern of the present and subsequent parts will be with initial segments of the countable upper semilattice D (≦0(1)) of degrees ≦0(1); a summary appeared in [21].