Hardware veri?cation is the process of checking whether a design
conforms to its speci?cations 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 re?ected by
developing and prod- tion statistics of present day companies. For
example, In?neon Technologies [118] assumed that about 60% to 80% of
the overall design time was spent for veri?cation in 2000. Other sources
cite the 3-to-1 head count ratio between veri?cation 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
dif?culty as well as the - portance of functional veri?cation of new
product designs has been increased. It is not only more important to get
error-free designs.
