Relational queries computable in polynomial time
Information and Control
Decidability and expressiveness aspects of logic queries
PODS '87 Proceedings of the sixth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Computation theory and logic
Principles of database and knowledge-base systems, Vol. I
Principles of database and knowledge-base systems, Vol. I
Inductive pebble games and the expressive power of datalog
PODS '89 Proceedings of the eighth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Proceedings of the 30th IEEE symposium on Foundations of computer science
Universality of data retrieval languages
POPL '79 Proceedings of the 6th ACM SIGACT-SIGPLAN symposium on Principles of programming languages
On Asymptotic Probability of Inductive Queries and Their Decision Problem
Proceedings of the Conference on Logic of Programs
The complexity of relational query languages (Extended Abstract)
STOC '82 Proceedings of the fourteenth annual ACM symposium on Theory of computing
Elementary induction on abstract structures (Studies in logic and the foundations of mathematics)
Elementary induction on abstract structures (Studies in logic and the foundations of mathematics)
On Datalog vs. polynomial time (extended abstract)
PODS '91 Proceedings of the tenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Datalog expressiveness of chain queries: grammar tools and characterizations
PODS '92 Proceedings of the eleventh ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Monotone monadic SNP and constraint satisfaction
STOC '93 Proceedings of the twenty-fifth annual ACM symposium on Theory of computing
PODS '94 Proceedings of the thirteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Bonded arity Datalog (≠) queries on graphs
PODS '94 Proceedings of the thirteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Adding disjunction to datalog (extended abstract)
PODS '94 Proceedings of the thirteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
On the relationship between description logic and predicate logic queries
CIKM '94 Proceedings of the third international conference on Information and knowledge management
Combinatorial games in database theory
PODS '95 Proceedings of the fourteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Programming with non-determinism in deductive databases
Annals of Mathematics and Artificial Intelligence
Annals of Mathematics and Artificial Intelligence
PADL '09 Proceedings of the 11th International Symposium on Practical Aspects of Declarative Languages
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We study here the language Datalog(≠), which is the query language obtained from Datalog by allowing equalities and inequalities in the bodies of the rules. We view Datalog(≠) as a fragment of an infinitary logic L&ohgr; and show that L&ohgr; can be characterized in terms of certain two-person pebble games. This characterization provides us with tools for investigating the expressive power of Datalog(≠). As a case study, we classify the expressibility of fixed subgraph homeomorphism queries on directed graphs. Fortune et al. [FHW80] classified the computational complexity of these queries by establishing two dichotomies, which are proper only if P ≠ NP. Without using any complexity-theoretic assumptions, we show here that the two dichotomies are indeed proper in terms of expressibility in Datalog(≠).