Guest Editors

Maria Fox
David E. Smith

Special Track Contents

The International Planning Competition Series began in 1998 and has been running biennially since that date. The competitions have been an important driver for research in the field. In particular, they have resulted in an evolving language for describing planning domains and problems (PDDL), a body of benchmark domains and problems in that language, and the ability to directly compare different generative planning techniques. All of this has contributed to significant advances in both the character and difficulty of problems that can be represented and solved by generative planning techniques.

The papers in this JAIR Special Track cover the 4th International Planning Competition (IPC-4), held in conjunction with the 14th International Conference on Planning and Scheduling (ICAPS-04). This competition marks the first time in which there has been a "probabilistic track" along with the continuing "classical" or "deterministic" track. As a result, the papers are divided into these two categories. The two overview papers (Edelkamp & Hoffmann, 2005) and (Younes et al, 2005) describe the language, structure and results of the classical and probabilistic competitions, respectively. The remaining papers describe the techniques and systems used in the competition. These papers include both standard Research Papers describing new techniques, and Engineering Notes describing the details of how a particular system was developed for competitive performance.