Cut-free Calculi and Relational Semantics for Temporal STIT Logics

We present cut-free labelled sequent calculi for a central formalism in logics of agency: STIT logics with temporal operators. These include sequent systems for Ldm , Tstit and Xstit. All calculi presented possess essential structural properties such as contraction- and cut-admissibility. The labelled calculi G3Ldm and G3Tstit are shown sound and complete relative to irreflexive temporal frames. Additionally, we extend current results by showing that also Xstit can be characterized through relational frames, omitting the use of BT+AC frames

Formal analysis of executions of organizational scenarios based on process-oriented specifications

Abstract This paper presents various formal techniques for analysis of executions of organizational scenarios based on specifications of organizations. Organizational specifications describe (prescribe) ordering and timing relations on organizational processes, modes of use of resources, allocations of actors to processes, etc. The actual execution may diverge from scenarios (pre)defined by a specification. A part of techniques proposed in this paper is dedicated to establishing the correspondence between a formalized execution (i.e., a trace) and the corresponding specification. Other techniques proposed in this paper provide the analyst with wide possibilities to evaluate organizational performance and to identify bottlenecks and other inefficiencies in the organizational operation. For the proposed formal analysis the order-sorted predicate Temporal Trace Language (TTL) is used and it is supported by the dedicated software tool TTL Checker. The analysis approaches considered in this paper are illustrated by a case study in the context of an organization from the security domain. © Springer Science+Business Media, LLC 2009

Logics of knowledge and action: critical analysis and challenges

International audienceWe overview the most prominent logics of knowledge and action that were proposed and studied in the multiagent systems literature. We classify them according to these two dimensions, knowledge and action, and moreover introduce a distinction between individual knowledge and group knowledge, and between a nonstrategic an a strategic interpretation of action operators. For each of the logics in our classification we highlight problematic properties. They indicate weaknesses in the design of these logics and call into question their suitability to represent knowledge and reason about it. This leads to a list of research challenges

A formalism unifying Defeasible Logics and Repair Semantics for existential rules

International audienceTwo prominent ways of handling inconsistency provided by the state of the art are repair semantics and Defeasible Logics. In this paper we place ourselves in the setting of inconsistent knowledge bases expressed using existential rules and investigate how these approaches relate to each other. We run an experiment that checks how human intuitions align with those of either repair-based or defeasible methods and propose a new semantics combining both worlds