Transformations that preserve learnability

Abstract

We consider transformations (performed by general recursive operators) mapping recursive functions into recursive functions. These transformations can be considered as mapping sets of recursive functions into sets of recursive functions. A transformation is said to be preserving the identification type I, if the transformation always maps I-identifiable sets into I-identifiable sets. There are transformations preserving FIN but not EX, and there axe transformations preserving EX but not FIN. However, transformations preserving EXi always preserve EXj for j < i.