Logic Programming -- The Well-Founded Semantics Is the Principle of Inductive Definition -- Combining Introspection and Communication with Rationality and Reactivity in Agents -- Disjunctive Logic Program = Horn Program + Control Program -- Semantics of Partial-Order Programs -- Epistemic Logics -- Persistence and Minimality in Epistemic Logic -- Prohairetic Deontic Logic (PDL) -- Phased Labeled Logics of Conditional Goals -- Theorem Proving -- Analysis of Distributed-Search Contraction-Based Strategies -- A Deduction Method Complete for Refutation and Finite Satisfiability -- Requirement-Based Cooperative Theorem Proving -- ?-Resolution: An Inference Rule for Regular Multiple-Valued Logics -- A Matrix Characterization for -- A Resolution Calculus for Dynamic Semantics -- Algorithms on Atomic Representations of Herbrand Models -- Non-monotonic Reasoning -- On the Intertranslatability of Autoepistemic, Default and Priority Logics, and Parallel Circumscription -- An Approach to Query-Answering in Reiter’s Default Logic and the Underlying Existence of Extensions Problem -- Towards State Update Axioms: Reifying Successor State Axioms -- Non-standard Logics -- A Mechanised Proof System for Relation Algebra Using Display Logic -- Relative Similarity Logics are Decidable: Reduction to FO2 with Equality -- A Conditional Logic for Belief Revision -- Implicates and Reduction Techniques for Temporal Logics -- A Logic for Anytime Deduction and Anytime Compilation -- Knowledge Representation -- On Knowledge, Strings, and Paradoxes -- Propositional Lower Bounds: Generalization and Algorithms -- Higher Order Logics -- Higher Order Generalization -- Invited Talks -- The Logical Characterization of Goal-Directed Behavior in the Presence of Exogenous Events Summary -- Towards Inference and Computation Mobility: The Jinni Experiment.

This volume contains the papers selected for presentation at the conference and two abstracts from invited speakers. The programme committee selected these 25 papers from 12 countries out of 65 submissions from 17 countries. The rst JELIA meeting was in Rosco , France, ten years ago. Afterwards, it took place in the Netherlands, Germany, United Kingdom, Portugal, and now again in Germany. The proceedings of the last four meetings appeared in the Springer-Verlag LNCS series, and a selected series of papers of the English and the Portuguese meeting appeared as special issues in the Journal of Applied Non-Classical Logics and in the Journal of Automated Reasoning, respectively. The aim of JELIA was and still is to provide a forum for the exchange of ideas and results in the domain of foundations of AI, focusing on rigorous descriptions of some aspects of intelligence. These descriptions are promoted by applications, and produced by logical tools and methods. The papers contained in this volume cover the following topics: 1. Logic programming 2. Epistemic logics 3. Theorem proving 4. Non-monotonic reasoning 5. Non-standard logics 6. Knowledge representation 7. Higher order logics We would like to warmly thank the authors, the invited speakers, the m- bers of the program committee, and the additional reviewers listed below. They all have made these proceedings possible and ensured their quality.