SOME RESULTS ON -COMPUTABLE STRUCTURES
WESLEY CALVERT AND JOHN E. PORTER
§1. Introduction. The theory of effectiveness properties on countable structures whose atomic diagrams are Turing computable is well-studied (see, for instance, [1, 15]). Typical results describe which structures in various classes are computable (or have isomorphic copies that are) , or the potential degree of unsolvability of various definable subsets of the structure . The goal of the present paper is to survey some initial results investigating similar concerns on structures which are effective in a different sense.
A rather severe limitation of the Turing model ...