Degrees of computability and randomness
Anthony Morphett · White Rose eTheses Online (University of Leeds, The University of Sheffield, University of York) · 2009
1 We defer a discussion of notation, definitions etc until sections 2 and 3, though our notation and terminology is standard.References for background, history, unexplained notation and definitions are Nies [60J and Downey and Hirschfeldt [20J.the notion of a c.e. set; if we think of the binary representation of a c.e. real x as giving the characteristic function of a set X, the set X need not be c.e.We will not use the notion of c.e. reals any further; when we write c.e. we mean it in the sense of a c.e. set.