Linkk Oping Electronic Articles in the Complexity of Model Checking in Modal Event Calculi with Quantiiers Linkk Oping Electronic Articles in Computer and Information Science

Kowalski and Sergot s Event Calculus EC is a simple tempo ral formalism that given a set of event occurrences derives the maximal validity intervals MVIs over which properties initi ated or terminated by these events hold It does so in polyno mial time with respect to the number of events Extensions of its query language with Boolean connectives and operators from modal logic have been shown to improve substantially its scarce expressiveness although at the cost of an increase in compu tational complexity However signi cant sublanguages are still tractable In this paper we further extend EC queries by admit ting arbitrary event quanti cation We demonstrate the added expressive power by encoding a hardware diagnosis problem in the resulting calculus We conduct a detailed complexity analy sis of this formalism and several sublanguages that restrict the way modalities connectives and quanti ers can be interleaved We also describe an implementation in the higher order logic programming language Prolog