This volume contains the contributions to the Joint German/Austrian Con- rence on Arti?cial Intelligence, KI 2001, which comprises the 24th German and the 9th Austrian Conference on Arti?cial Intelligence. – 29 accepted technical papers, of which 5 where submitted as application papers and 24 as papers on foundations of AI;

Invited Contributions.- Computational Game Theory and AI.- Optimal Agent Section.- Selected Papers.- Towards First-Order Temporal Resolution.- Approximating Most Specific Concepts in Description Logics with Existential Restrictions.- Bayesian Learning and Evolutionary Parameter Optimization.- Papers on Foundations.- Abductive Partial Order Planning with Dependent Fluents.- Constraint-Based Optimization of Priority Schemes for Decoupled Path Planning Techniques.- Possible Worlds Semantics for Credulous and Contraction Inference.- The Point Algebra for Branching Time Revisited.- Exploiting Conditional Equivalences in Connection Calculi.- Propositional Satisfiability in Answer-Set Programming.- Prediction of Regular Search Tree Growth by Spectral Analysis.- Theory and Practice of Time-Space Trade-Offs in Memory Limited Search.- Hierarchical Diagnosis of Large Configurator Knowledge Bases.- Towards Distributed Configuration.- Belief Update in the pGOLOG Framework.- Finding Optimal Solutions to Atomix.- History-Based Diagnosis Templates in the Framework of the Situation Calculus.- A Defense Model for Games with Incomplete Information.- Towards Inferring Labelling Heuristics for CSP Application Domains.- Addressing the Qualification Problem in FLUX.- Extracting Situation Facts from Activation Value Histories in Behavior-Based Robots.- Learning Search Control Knowledge for Equational Theorem Proving.- Intelligent Structuring and Reducing of Association Rules with Formal Concept Analysis.- Comparing Two Models for Software Debugging.- Inferring Implicit State Knowledge and Plans with Sensing Actions.- Papers on Applications.- Multi-agent Systems as Intelligent Virtual Environments.- OilEd: A Reason-able Ontology Editor for the Semantic Web.- Experiments with an Agent-Oriented Reasoning System.- Learning to Execute Navigation Plans.- DiKe - A Model-Based Diagnosis Kernel and Its Application.- Industrial Papers.- Constraints Applied to Configurations.- From Theory to Practice: AI Planning for High Performance Elevator Control.- Semantic Networks in a Knowledge Management Portal.- Collaborative Supply Net Management.