Counting Answers to Existential Positive Queries: A Complexity Classification
Databases
2016-04-21 v2 Computational Complexity
Abstract
Existential positive formulas form a fragment of first-order logic that includes and is semantically equivalent to unions of conjunctive queries, one of the most important and well-studied classes of queries in database theory. We consider the complexity of counting the number of answers to existential positive formulas on finite structures and give a trichotomy theorem on query classes, in the setting of bounded arity. This theorem generalizes and unifies several known results on the complexity of conjunctive queries and unions of conjunctive queries.
Cite
@article{arxiv.1601.03240,
title = {Counting Answers to Existential Positive Queries: A Complexity Classification},
author = {Hubie Chen and Stefan Mengel},
journal= {arXiv preprint arXiv:1601.03240},
year = {2016}
}
Comments
arXiv admin note: substantial text overlap with arXiv:1501.07195