Hierarchical specification of system behavior

Complex systems are commonly broken up into a hierarchy of composed components. This methodology reduces the complexity of the system os a whole and allows teams of designers to attack the problem of definition. We present and propose a hierarchical methodology for the specification of the behaviors of complex designs. We introduce a single BY operator, such that A BY B means “A is true because of the arbitrarily repeated assertion of the truth of B”. We show its application in the temporal logic of UNITY and present example uses of the BY operator in specifications of complex systems. Usage of the BY operator induces a hierarchy in the specification of the behavior of a system which often corresponds well to the decomposition of the design definition