In view of the recent interest in a short proof of the Jacobi identity for the Poisson-brackets, we provide an alternative simple proof for the same. Our derivation is based on the validity of the Leibnitz rule in the context of dynamical evolution.

We analyze a model in which voters learn over time their preferences regarding an irreversible social decision. Voters can either implement the project in the first period, or they can postpone the decision to the second period. We analyze the effects of different majority rules. We show that individual first period voting behavior may become “less conservative” under supermajority rules, and t...

A conflicting knowledge base can be seen abstractly as a set of arguments and a binary relation characterising conflict among them. There may be multiple plausible ways to evaluate conflicting arguments. In this paper, we ask: given a set of agents, each with a legitimate subjective evaluation of a set of arguments, how can they reach a collective evaluation of those arguments? After formally d...

Many works have focused, for over twenty five years, on the integration of the time dimension in databases (DB). However, the standard SQL3 does not yet allow easy definition, manipulation and querying of temporal DBs. In this paper, we study how we can simplify querying and manipulating temporal facts in SQL3, using a model that integrates time in a native manner. To do this, we propose new ke...

A network of peer database management systems differs from conventional multidatabase systems by assuming absence of any central control, no global schema, transient connection of participating peer DBMSs, and evolving coordination among databases. We describe distributed triggers to support data coordination in this setting. The execution of our triggers requires coordination among the involve...

This paper gives a new flavor of what Peter Jagers and his co-authors call ‘the path to extinction’. In a neutral population with constant size N , we assume that each individual at time 0 carries a distinct type, or allele. We consider the joint dynamics of these N alleles, for example the dynamics of their respective frequencies and more plainly the nonincreasing process counting the number o...

Bei der Anwendungsentwicklung werden komponentenbasierte Methoden bereits erfolgreich eingesetzt. Beim objekt-relationalen Schemaentwurf ist dies allerdings noch nicht der Fall. Dies liegt u.a. daran, dass Konzepte, die einen solchen Entwurf unterstützen, noch nicht im Standard SQL:1999 enthalten sind. In diesem Aufsatz stellen wir Ansätze zur Klassifikation verschiedener Module in objekt-relat...

In automotive R&D projects a major part of development cost is caused by tests which utilize expensive experimental vehicles. In this paper, we introduce an approach for scheduling the individual tests such that the number of required experimental vehicles is minimized. The proposed approach is based on a new type of multi-mode resource-constrained project scheduling model with minimum and maxi...