Published online by Cambridge University Press: 12 March 2014
The well-developed theory of recursion has been applied to certain algebraic structures with countable universes to obtain interesting and natural results on the question of effective procedures in such structures ([2], [9], [10], [13]). It has also been applied to structures related to the real numbers, via approximations; we cite [3] as but one example. We are interested, however, in the problem of what operations in an arbitrary algebraic structure, possibly quite large and unnatural, can reasonably be considered “effective” in terms of the underlying operations and relations of the structure.