Invited Talks -- Is Computational Complexity a Barrier to Manipulation? -- Games, Norms and Strategic Notions in Information Flow Security -- Group Announcements: Logic and Games (Abstract of Invited Talk) -- Strong Equivalence in Argumentation -- Regular Papers -- Hypergraphs of Multiparty Secrets -- Combining Logics in Simple Type Theory -- Speculative Abductive Reasoning for Hierarchical Agent Systems -- Formal Semantics of a Dynamic Epistemic Logic for Describing Knowledge Properties of ?-Calculus Processes -- What Happened to My Commitment? Exception Diagnosis among Misalignment and Misbehavior -- Verifying Business Process Compliance by Reasoning about Actions -- From Organisation Specification to Normative Programming in Multi-Agent Organisations -- Finding Uniform Strategies for Multi-agent Systems -- Playing Extensive Form Games in Parallel -- Exploring the Boundary of Half Positionality -- Proof-Theoretic Analysis of Rationality for Strategic Games with Arbitrary Strategy Sets -- An Agent Language with Destructive Assignment and Model-Theoretic Semantics -- Model Checking Agent Programs by Using the Program Interpreter -- A Dialogue Games Framework for the Operational Semantics of Logic Agent-Oriented Languages.

These are the proceedings of the 11th International Workshop on Compu- tional Logicin Multi-Agent Systems (CLIMA-XI), held during August 16–17,in Lisbon, collocated with the 19th European Conference on Arti?cial Intelligence (ECAI-2010). Multi-agentsystemsarecommunitiesofproblem-solvingentitiesthatcanp- ceive and act upon their environment in order to achieve both their individual goals and their joint goals. The work on such systems integrates many techno- giesandconceptsfromarti?cialintelligenceandotherareasofcomputingaswell as other disciplines. Over recent years, the agent paradigm gained popularity, due to its applicability to a full spectrum of domains, such as search engines, recommendation systems, educational support, e-procurement, simulation and routing,electroniccommerceandtrade,etc.Computationallogicprovidesawe- de?ned, general, and rigorousframeworkfor studying the syntax, semantics and procedures for the various tasks in individual agents, as well as the interaction between, and integration among, agents in multi-agent systems. It also provides tools, techniques and standards for implementations and environments, for li- ing speci?cations to implementations, and for the veri?cation of properties of individual agents, multi-agent systems and their implementations. The purpose of the CLIMA workshops is to provide a forum for discussing techniques, based on computational logic, for representing, programming and reasoning about agents and multi-agent systems in a formal way. Former CLIMA editions have been conducted in conjunction with other - jor Computational Logic and AI events such as CL in 2000, ICLP in 2001 and 2007, FLoC in 2002, LPNMR and AI-Math in 2004, JELIA in 2004 and 2008 and MATES in 2009. In 2005 CLIMA was not associated with any major event.