Appendix E : Alternative Approaches

I chose these four approaches because of their ability to capture complex structure succinctly and abstractly. They are all well known, and each has an active and enthusiastic community of users and researchers. Other modeling and analysis approaches can be used effectively for software design in specialized domains: there are many model checkers, for example, that can check protocols and concurrent algorithms, but they are not considered here since (with the exception of FDR) they tend to have only rudimentary support for structuring of data.