Term Rewriting in Logics of Partial Functions

We devise a theoretical foundation of directed rewriting, a term rewriting strategy for logics of partial functions, inspired by term rewriting in the Rodin platform. We prove that directed rewriting is sound and show how to supply new rewrite rules in a soundness preserving fashion. In the context of Rodin, we show that directed rewriting makes a signicant number of conditional rewrite rules unconditional. Our work not only allows us to point out a number of concrete ways of improving directed rewriting in Rodin, but also has applications in other logics of partial functions. Additionally, we give a semantics for the logic of Event-B

Branching vs. Linear Time: Final Showdown

The discussion of the relative merits of linear- versus branching-time frameworks goes back to early 1980s. One of the beliefs dominating this discussion has been that "while specifying is easier in LTL (linear-temporal logic), verification is easier for CTL (branching-temporal logic)". Indeed, the restricted syntax of CTL limits its expressive power and many important behaviors (e.g., strong fairness) can not be specified in CTL. On the other hand, while model checking for CTL can be done in time that is linear in the size of the specification, it takes time that is exponential in the specification for LTL. Because of these arguments, and for historical reasons, the dominant temporal specification language in industrial use is CTL

Continued operation of a 25-raingage network for collection, reduction, and analysis of precipitation data for Lake Michigan diversion accounting: Water year 2002

"Final report to the U.S. Army Corps of Engineers, Chicago District and U.S. Geological Survey.""February 2003.