Abstract families of length-preserving processors

• Authors: Sister Teresemarie McCloskey
• Venue: Journal of Computer and System Sciences
• Year: 1975

A ''length-preserving processor'', is in essence a nondeterministic linear bounded automaton with auxiliary storage. Length-preserving processors are partitioned into classes according to their methods of handling storage, and each class is termed an ''abstract family of length-preserving processors'' (AFLP). The smallest AFLP, i.e. the family of linear bounded automata, and the family of context-sensitive languages defined by it are characterized as the smallest families having certain containment and closure properties. These properties motivate the definition of an ''abstract family of length-preserving operations,'' (AFLO), and a ''closed abstract, family of languages'' (closed AFL). Every AFLP computes an AFLO and each of a broad class of storage-bounded subfamilies of an AFLP computes an AFLO or a