The homogeneity conjecture.
We show that, for any function f in which Kleene's O is computable, the ordering of Turning degrees (i.e., degrees of difficulty of computation of functions) is not isomorphic to the ordering of degrees of functions from which f is computable. This refutes a well-known conjecture of H. Rogers, Jr., and others.
Shore
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Department of Mathematics, Cornell University, Ithaca, New York 14853.