Principles of database and knowledge-base systems, Vol. I
Principles of database and knowledge-base systems, Vol. I
Decidable optimization problems for database logic programs
STOC '88 Proceedings of the twentieth annual ACM symposium on Theory of computing
Expressiveness of restricted recursive queries
STOC '89 Proceedings of the twenty-first annual ACM symposium on Theory of computing
On the first-order expressibility of recursive queries
PODS '89 Proceedings of the eighth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
PODS '91 Proceedings of the tenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Graph rewriting: an algebraic and logic approach
Handbook of theoretical computer science (vol. B)
Undecidable optimization problems for database logic programs
Journal of the ACM (JACM)
Bounded arity Datalog ( ≠ ) queries on graphs
Journal of Computer and System Sciences - Special issue on principles of database systems
Conjunctive-query containment and constraint satisfaction
PODS '98 Proceedings of the seventeenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Hypertree decompositions and tractable queries
PODS '99 Proceedings of the eighteenth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Decidability and undecidability results for boundedness of linear recursive queries
Proceedings of the seventh ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Journal of the ACM (JACM)
Achilles, Turtle, and Undecidable Boundedness Problems for Small DATALOG Programs
SIAM Journal on Computing
Foundations of Databases: The Logical Level
Foundations of Databases: The Logical Level
Computers and Intractability: A Guide to the Theory of NP-Completeness
Computers and Intractability: A Guide to the Theory of NP-Completeness
Datalog programs and their persistency numbers
ACM Transactions on Computational Logic (TOCL)
Introduction to Automata Theory, Languages, and Computation (3rd Edition)
Introduction to Automata Theory, Languages, and Computation (3rd Edition)
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The relation between Datalog programs and homomorphism problems, and, between Datalog programs and bounded treewidth structures has been recognized for some time and given much attention recently. Additionally, the essential role of persistent variables (in program expansions) for solving several relevant problems has also started to be observed. In Afrati et al. [2005] the general notion of program persistencies was refined into four notions (two syntactical ones and two semantical ones) and the interrelationship between these four persistency numbers was studied. In the present article (1) we prove undecidability results concerning the semantical notions of persistency number--modulo equivalence, of persistency number and of characteristic integer, (2) we exhibit new classes of programs for which boundedness is undecidable and (3) we prove intractabiltity results concerning the syntactical notions of weak persistency number and of weak characteristic integer.