redlog is a system for computing with first-order logic and propositional logic with quantification. It is tightly integrated into the computer algebra system reduce. Assuming a broad audience, we motivate the use of first-order logic to model problems. Then, by employing quantifier elimination methods, simplification techniques and normal form computations, highly non-trivial problems can be s...

Two uid-ow problems are solved using perturbation expansions, with special emphasis on the reduction of intermediate expression swell. This is done by developing tools in Maple that contribute to the eecient representation and manipulation of large expressions. The tools share a common basis, which is the creation of a hierarchy of representation levels such that expressions located at higher l...

The study of computational agents capable of rational behaviour has received a great deal of attention in recent years. Theoretical formalizations of such agents and their implementations have proceeded in parallel with little or no connection between them. Tkis paper explores a particular type of rational agent, a BeliefDesire-Intention (BDI) agent. The primary aim of this paper is to integrat...

The observation of a distributed system’s finite execution can be abstracted as a partial ordered set of events generally called finite (partial order) trace. In practice, this trace can be obtained through a standard code instrumentation, which takes advantage of existing communications between processes to partially order events of different processes. We show that testing that such a distrib...

We study the behavioural theory of a higher-order distributed calculus with private names and locations that can be passivated. For this language, we present a novel Labelled Transition System where higher-order inputs are symbolic agents that can perform a limited number of transitions, capturing the nature of passivation. Standard first-order weak bisimulation over this LTS coincides with con...

Higher-order pushdown systems (PDSs) generalise pushdown systems through the use ofhigher-order stacks, that is, a nested “stack of stacks” structure. These systems may be usedto model higher-order programs and are closely related to the Caucal hierarchy of infinitegraphs and safe higher-order recursion schemes.We consider the backwards-reachability problem over higher-order Alt...