Hyper tableaux -- An algorithm for the retrieval of unifiers from discrimination trees -- Building proofs or counterexamples by analogy in a resolution framework -- What you always wanted to know about rigid E-unification -- Labelled proofs for quantified modal logic -- A uniform tableaux method for nonmonotonic modal logics -- Design and implementation of diagnostic strategies using modal logic -- A modal action logic based framework for organization specification and analysis -- McCarthy's idea -- Strong and explicit negation in non-monotonic reasoning and logic programming -- Only persistence makes nonmonotonicity monotonous -- Ordering-based representations of rational inference -- Semi-representability of default theories in rational default logic -- A query answering algorithm for Lukaszewicz' general open default theory -- Infinitary default logic for specification of nonmonotonic reasoning -- A system for computing constrained default logic extensions -- The Oz programming model -- An abductive framework for negation in disjunctive logic programming -- Characterizing D-WFS: Confluence and iterated GCWA -- Modules and specifications -- Logic programming with integrity constraints -- Temporal reasoning over linear discrete time -- Similarity saturation for first order linear temporal logic with UNLESS -- Carving Up space: Steps towards construction of an absolutely complete theory of spatial regions -- Informational logic for automated reasoning -- Extensions for open default theories via the domain closure assumption -- Revising and updating using a back-up semantics -- A simple signed system for paraconsistent reasoning.

This book presents the refereed proceedings of the Sixth European Workshop on Logics in Artificial Intelligence, JELIA '96, held in Evora, Portugal in September/October 1996. The 25 revised full papers included together with three invited papers were selected from 57 submissions. Many relevant aspects of AI logics are addressed. The papers are organized in sections on automated reasoning, modal logics, applications, nonmonotonic reasoning, default logics, logic programming, temporal and spatial logics, and belief revision and paraconsistency.