Deciding boundedness of monadic sirups
Computational Complexity
2021-08-03 v1
Abstract
We show that deciding boundedness (aka FO-rewritability) of monadic single rule datalog programs (sirups) is 2Exp-hard, which matches the upper bound known since 1988 and finally settles a long-standing open problem. We obtain this result as a byproduct of an attempt to classify monadic `disjunctive sirups' -- Boolean conjunctive queries q with unary and binary predicates mediated by a disjunctive rule T(x)vF(x) <- A(x) -- according to the data complexity of their evaluation. Apart from establishing that deciding FO-rewritability of disjunctive sirups with a dag-shaped q is also 2Exp-hard, we make substantial progress towards obtaining a complete FO/L-hardness dichotomy of disjunctive sirups with ditree-shaped q.
Keywords
Cite
@article{arxiv.2108.00433,
title = {Deciding boundedness of monadic sirups},
author = {Stanislav Kikot and Agi Kurucz and Vladimir Podolskii and Michael Zakharyaschev},
journal= {arXiv preprint arXiv:2108.00433},
year = {2021}
}