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Next: A Subtle Point: Actions Up: Environment and Interfaces Previous: Abstraction

Actions Revisited

By combining the two points made in the previous two subsections we see that we can divide a set of actions into external and internal actions. We can further divide a set of external actions into input and output actions. Different models of state machines may or may not make these distinctions. For example, the I/O automata model developed by Nancy Lynch and her students at MIT makes both distinctions.

Norman Papernick
Mon Mar 18 13:45:16 EST 1996