The importance of Π10 classes in effective randomness
George Barmpalias, Andrew E. M. Lewis, Keng Meng Ng · Journal of Symbolic Logic · 2010
Abstract We prove a number of results in effective randomness, using methods in which Π10 classes play an essential role. The results proved include the fact that every PA Turing degree is the join of two random Turing degrees, and the existence of a minimal pair of LR degrees below the LR degree of the halting problem.