BIB-VERSION:: CS-TR-v2.0
          ID:: SBCS//stark/ioauto.dvi
       ENTRY:: July 24, 1994
ORGANIZATION:: State University of New York at Stony Brook, Computer Science
       TITLE:: A Proof of the Kahn Principle for Input/Output Automata
        TYPE:: Preprint
      AUTHOR:: Lynch, Nancy A., Stark, Eugene W.
     CONTACT:: Eugene W. Stark, Department of Computer Science,
                   SUNY at Stony Brook, Stony Brook, NY 11794-4400
                   Tel: 516-632-8444 <stark@cs.sunysb.edu>
	DATE:: June, 1989
   RETRIEVAL:: HTTP from BSD7.CS.SUNYSB.EDU with the URL
		   http://bsd7.cs.sunysb.edu/~stark/REPORTS/ioauto.ps.gz
       NOTES:: A version of this paper appeared as:
                   N. A. Lynch, E. W. Stark
                   "A Proof of the Kahn Principle for Input/Output Automata,"
                   Information and Computation
                   Volume 82, Number 1 (July, 1989)
                   pp. 81-92

ABSTRACT::

We use *input/output automata* to define a simple and general
model of networks of concurrently executing, nondeterministic
processes that communicate through unidirectional, named *ports*.
A notion of the *input/output relation* computed by a process is
defined, and *determinate* processes are defined to be processes
whose input/output relations are single-valued.  We show that
determinate processes compute continuous functions, and that networks
of determinate processes obey *Kahn's fixed-point principle*.
Although these results are already known, our contribution lies in the
fact that the input/output automata model yields extremely simple
proofs of them (the simplest we have seen), in spite of its generality.

END:: SBCS//stark/ioauto.dvi