Low upper bounds of ideals
Antonín Kučera, Theodore A. Slaman · Journal of Symbolic Logic · 2009
Abstract We show that there is a lowT-upper bound for the class ofK-trivial sets, namely those which are weak from the point of view of algorithmic randomness. This result is a special case of a more general characterization of ideals in T-degrees for which there is a lowT-upper bound.