Approximation representations for $\Delta^0_2$ reals
G. Barmpalias
Summary
We study $\Delta^0_2$ reals in terms of how they can be approximated
symmetrically by a computable sequence of rationals. We deal
with a natural notion of approximation representation and study how
these are related computationally for a fixed real. This is a continuation of
earlier work; it aims at a classification of $\Delta^0_2$ reals based on approximation
and it turns out to be quite different than the existing ones (based
on information content etc.)