Abstract families of processors
Gene F. Rose · 1969
A “processor” is a Turing-like automaton with auxiliary storage. An “abstract family” of processors (AFP) consists of all processors that use the storage in the same way. Properties common to all AFP are derived. For a family of operations to be the output functions of some AFP, it is necessary and sufficient that certain word-sets representing its members form a full AFL (in the sense of Ginsburg and Greibach) closed under intersection and iterated finite substitution.2 For a family of word-sets to be the accepted languages of some AFP, it is necessary and sufficient that it be a full AFL closed under intersection and iterated finite substitution. The smallest full AFL of this kind is the family of all recursively enumerable sets.