Dennis de Champeaux

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Aliasing has been a problem in both formal verification and practical programming for a number of years. To the formalist, it can be annoyingly difficult to prove the simple Hoare formula {x = true} y := false {x = true}. If x and y refer to the same boolean variable, i.e., x and y are <i>aliased</i>, then the formula will not be valid, and proving that(More)
Extenswe modificaUons of a previously published bidirectional heuristic search algorithm are presented in order to preserve the property that shortest solutions are found under approprmte circumstances. Theoretical results encompass the generahzation of the unidirectional optimahty theorem Unidirectional heuristic search is a well-understood area in(More)
Properties are proved about INSTANCE, a theorem prover module that recognizes that a formula is a special case and/or an alphabetic variant of another formula, and about INSURER, another theorem prover module that decomposes a problem, represented by a formula, into independent subproblems, using a conjunction. The main result of INSTANCE is soundness; the(More)
object-oriented analysis, design and implementation methods These are the highlights of a successfully completed application of object-oriented software development for a new product. The project was of medium size, the duration was less than 24 months (from the end of the requirements specification to product shipment), and the average team size was 8-10(More)
Statecharts are extended to deal with events when no applicable transition is available, and to resolve conflicts relative to event scheduling and response that can arise whenever multiple states can be active simultaneously. "Event closure" and event scheduling are achieved without having to clutter up a basic statechart. The extensions are effected by(More)