Published online by Cambridge University Press: 15 August 2002
Ordered binary decision diagrams are an important data structure for the representation of Boolean functions.Typically, the underlying variable ordering is used as an optimization parameter.When finite state machines are represented by OBDDsthe state encoding can be used as an additionaloptimization parameter. In this paper, we analyze the influence of the state encoding on theOBDD-representations of counter-type finite state machines.In particular, we prove lower bounds, deriveexact sizes for importantencodings and construct a worst-case encoding which leads to exponential-size OBDDs.