Implementation of logical query languages for databases
ACM Transactions on Database Systems (TODS)
Magic sets and other strange ways to implement logic programs (extended abstract)
PODS '86 Proceedings of the fifth ACM SIGACT-SIGMOD symposium on Principles of database systems
Convergence of sideways query evaluation
PODS '86 Proceedings of the fifth ACM SIGACT-SIGMOD symposium on Principles of database systems
An amateur's introduction to recursive query processing strategies
SIGMOD '86 Proceedings of the 1986 ACM SIGMOD international conference on Management of data
Efficient tests for top-down termination of logical rules
Journal of the ACM (JACM)
Termination detection in logic programs using argument sizes (extended abstract)
PODS '91 Proceedings of the tenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
On the complexity of dataflow analysis of logic programs
ACM Transactions on Programming Languages and Systems (TOPLAS)
Deriving constraints among argument sizes in logic programs (extended abstract)
PODS '90 Proceedings of the ninth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
| Hi-index | 0.00 |
Capture rules were introduced in [U] as a method for planning the evaluation of a query expressed in first-order logic. We examine a capture rule that is substantiated by a simple top-down implementation of restricted Horn clause logic. A necessary and sufficient condition for the top-down algorithm to converge is shown. It is proved that, provided there is a bound on the number of arguments of predicates, the test can be performed in polynomial time; however, if the arity of predicates is made part of the input, then the problem of deciding whether the top-down algorithm converges is NP-hard. We then consider relaxation of some of our constraints on the form of the logic, showing that success of the top-down algorithm can still be tested in polynomial time if the number of arguments is limited and in exponential time if not.