Hardware verification is the process of checking whether a design conforms to its specifications of functionality and timing. In today’s design processes it becomes more and more important. Very large scale integrated (VLSI) circuits and the resulting digital systems have conquered a place in almost all areas of our life, even in security sensitive applications. Complex digital systems control airplanes, have been used in banks and on intensive-care units. Hence, the demand for error-free designs is more important than ever. In addition, economic reasons underline this demand as well. The design and production process of present day VLSI-circuits is highly time- and cost-intensive. Mo- over, it is nearly impossible to repair integrated circuits. Thus, it is desirable to detect design errors early in the design process and not just after producing the prototype chip. All these facts are reffected by developing and prod- tion statistics of present day companies. For example, Infineon Technologies [118] assumed that about 60% to 80% of the overall design time was spent for verification in 2000. Other sources cite the 3-to-1 head count ratio between verification engineers and logic designers. This shows that verifying logical correctness of the design of hardware systems is a major gate to the problem of time-to-market (cf. [113]). With the chip complexity constantly increasing, the difficulty as well as the - portance of functional verification of new product designs has been increased. It is not only more important to get error-free designs.