Lists
Lists
Kikot, Stanislav, Kontchakov, Roman, Podolskii, Vladimir and Zakharyaschev, Michael (2014) On the succinctness of query rewriting over shallow ontologies. In: CSL/LICS 2014: Joint Meeting of the Twenty-Third EACSL Annual Conference on Computer Science Logic and the Twenty-Ninth Annual ACM/IEEE Symposium on Logic in Computer Science, 14- 18 July 2014, Vienna, Austria.
We investigate the size of first-order rewritings of conjunctive queries overOWL 2 QLontologies ofdepth 1 and 2 by means of hypergraph programs computing Boolean functions. Both positive and neg-ative results are obtained. Conjunctive queries over ontologies of depth 1 have polynomial-size nonre-cursive datalog rewritings; tree-shaped queries have polynomial positive existential rewritings; however,in the worst case, positive existential rewritings can only be of superpolynomial size. Positive existentialand nonrecursive datalog rewritings of queries over ontologies of depth 2 suffer an exponential blowup in the worst case, while first-order rewritings are superpolynomial unless NP⊆P/poly. We also analyserewritings of tree-shaped queries over arbitrary ontologies and observe that the query entailment problemfor such queries is fixed-parameter tractable.
 |
View Item |