This interdisciplinary research is carried out in a collaboration between Professors Phokion Kolaitis at the University of California, Santa Cruz and Moshe Vardi at Rice University. Constraint satisfaction and conjunctive query evaluation are two fundamental and ubiquitous problems in artificial intelligence and database systems, respectively. Since these problems are known to be computationally intractable in the worst case, researchers in artificial intelligence and database systems have sought to discover tractable cases of constraint satisfaction and conjunctive query evaluation, as well as to design heuristic algorithms for solving these problems. Thus far, however, these studies have been largely carried out in parallel and with relatively little or no interaction between the two areas. Recent research work has established that there are strong and exact connections between constraint satisfaction and conjunctive query evaluation. The main goal of this project is to further explore the connections between constraint satisfaction and conjunctive query evaluation, and to examine the applicability of techniques developed for each of these problems to the other problem. To this effect, a novel game-theoretic framework is being developed to unify seemingly unrelated results, identify additional tractable cases of these two problems, and design heuristics for the general case. Moreover, algorithms and heuristics developed by the artificial intelligence community are being evaluated in regards to their efficacy in conjunctive query evaluation, and vice versa. Results obtained in the course of this project will enhance the interaction between artificial intelligence and database systems, and will advance knowledge transfer between these two areas.
