System behaviors are defined through finite-state generators and “acceptors” of behavior, known generally as “finite state machines” and “finite state automata”, respectively. In case all behavior is eventually terminating (bounded in time), each behavior is captured by a*string*of events. (Nonterminating (unbounded) behavior, captured by sequences of events, is dealt with analogously in Chapter 6). There are reasons, discussed in Section 6.2, for wanting, in both the bounded and infinite cases, two distinct types of structures for defining behavior: the*process*in the role of behavior generator, and the*automaton*in the role of acceptor. The acceptor or automaton