A.2 Composite Processes

A.2 Composite Processes

A composite process is the parallel composition of one or more processes. The definition of a composite process is preceded by ||.

Example

 ||Composite = (P || Q).

Table A.2: Composite process operators

Parallel Composition ||	If P and Q are processes then (P||Q) represents the concurrent execution of P and Q.
Replicator forall	forall [i:1..N] P(i) is the parallel composition (P(1)||...||P(N)).
Process Labeling :	a:P prefixes each label in the alphabet of P with a.
Process Sharing ::	{a1,..,ax}::P replaces every label n in the alphabet of P with the labels a1.n,...,ax .n. Further, every transition (n->Q) in the definition of P is replaced with the transitions ({a1.n,...,ax .n}->Q).
Priority High <<	||C =(P||Q)<<{a1 ,...,an } specifies a composition in which the actions a1,...,an have higher priority than any other action in the alphabet of P||Q including the silent action tau. In any choice in this system which has one or more of the actions a1,...,an labeling a transition, the transitions labeled with lower priority actions are discarded.
Priority Low >>	||C=(P||Q)>>{a1 ,...,an} specifies a composition in which the actions a1,...,an have lower priority than any other action in the alphabet of P||Q including the silent action tau. In any choice in this system which has one or more transitions not labeled by a1,...,an, the transitions labeled by a1,...,an are discarded.