# Accession Number:

## AD0697040

# Title:

## TWO CHARACTERISTIZATIONS OF THE CONTEXT-SENSITIVE LANGUAGES,

# Descriptive Note:

# Corporate Author:

## CARNEGIE-MELLON UNIV PITTSBURGH PA DEPT OF COMPUTER SCIENCE

# Personal Author(s):

# Report Date:

## 1969-09-01

# Pagination or Media Count:

## 15.0

# Abstract:

An n-dimensional bug-automation is a generalization of a finite state acceptor to n-dimensions. With each bug B, is associated the language LB which is the set of top rows of n-dimensional rectangular arrays accepted by B. One-dimensional bugs define trivially the regular sets. Two-dimensional bugs define precisely the context-sensitive languages, while bugs of dimension 3 or greater define all the recursively enumerable sets. Finite state acceptors with n two-way non-writing input tapes are also considered. For each such machine M, let domain M be the set of all strings which are the first component of some n-tuple of tapes accepted by M. For any n or 1, the domains of n-tape finite state acceptors are precisely the same as the languages definable by n-dimensional bugs, so as a corollary, the domains of two-tape two-way finite state acceptors are precisely the contest-sensitive languages. Author

# Descriptors:

# Subject Categories:

- Linguistics
- Computer Programming and Software
- Bionics