Published online by Cambridge University Press: 12 March 2014
Let ƒ be a real number. It is well known [7] that the setof rational numbers which are less than ƒ is a recursiveset if and only if ƒ is representable as the limit of arecursive, recursively convergent sequence of rational numbers. In thispaper we replace the condition that the set of rational numbers less than ƒ is recursive by the condition that this set is atvarious points in the Kleene hierarchy, and we replace the recursive,recursively convergent limit by a variety of other recursive limitingprocesses.