In
computer science and
mathematical logic the
Turing degree (named after
Alan Turing) or
degree of unsolvability of a set of natural numbers measures the level of algorithmic unsolvability of the set. The concept of Turing degree is fundamental in
computability theory, where sets of natural numbers are often regarded as
decision problems. The Turing degree of a set tells how difficult it is to solve the decision problem associated with the set, that is, to determine whether an arbitrary number is in the given set.