An extensional fixed-point semantics for nondeterministic data flow

AbstractA fixed point semantics for nondeterministic data flow is introduced which refines and extends work of Park (1983). It can be seen also as an extension to the general case of Kahn's (1974) successful fixed point semantics for deterministic data flow. An associativity result for network construction is proved which shows that anomalies such as those of Brock and Ackerman do not arise in this semantics. The semantics is shown to be extensional, in the natural sense that nondeterministic processes which induce identical input-output relations in all contexts are equal