ABSTRACT
Representations were first effectively analyzed by Calude, Coles, Hertling, and Khoussainov [7]. We have seen that if a real is c.e. then it has a computable representation. If a real is computable then every representation must be computable (exercise). Suppose that a c.e. real is noncomputable. What else can be said about its representations? For instance, the natural degree of a c.e. real is the degree of its left cut: deg L(a). Does a always have a representation of degree degL(a)? of other degrees?
