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Polynomial Datalog Rewritings for Expressive Description Logics with Closed Predicates
TLDR
To the best of the knowledge, this is the first polynomial time translation of an expressive (non-Horn) DL into disjunctive DATALOG. Expand
Managing Change in Graph-Structured Data Using Description Logics
TLDR
This article formalizes the preceding data management problems as a static verification problem and several planning problems and shows that, due to the adequate choice of formalisms for describing actions and states of the data, most of theseData management problems can be effectively reduced to the (un)satisfiability of suitable formulas in decidable logical formalisms. Expand
Polynomial Datalog Rewritings for Ontology Mediated Queries with Closed Predicates
TLDR
This work investigates the relative expressiveness of OMQs in terms of more traditional query languages like Datalog, and focuses on the following problem: given an OMQ Q, obtain a Datalogs query Q′—in a suitable fragment—such that the certain answers to Q and Q′ coincide. Expand
Towards Reconciling SPARQL and Certain Answers
TLDR
This work presents algorithms for the evaluation of an interesting fragment of SPARQL and shows that the complexity of the most fundamental query analysis tasks is not negatively affected by the presence of OWL 2 QL entailment under the proposed semantics. Expand
Rewriting Guarded Existential Rules into Small Datalog Programs
TLDR
A two-player game that characterizes the satisfaction of the dependencies is defined, and a Datalog query that can decide the existence of a winning strategy for the game is designed that requires only polynomial time. Expand
Rewriting Approaches for Ontology-Mediated Query Answering
TLDR
Novel rewriting approaches for several extensions of OBDA are presented to understand their relative expressiveness and to pave the way for efficient query answering algorithms. Expand
Polynomial Rewritings from Expressive Description Logics with Closed Predicates to Variants of Datalog
TLDR
The central goal of this paper is to understand the relative expressiveness of ontology-mediated query languages in which the ontology part is written in the expressive Description Logic (DL) ALCHOI and includes a set of closed predicates. Expand
Polynomial Disjunctive Datalog Rewritings of Instance Queries in Expressive Description Logics
TLDR
This paper proposes a translation of instance queries mediated by ontologies in the expressive DL ALCHI, into polynomial-sized disjunctive Datalog programs, based on a simple game-like algorithm, and can be extended to accommodate nominals. Expand
The Challenge of Optional Matching in SPARQL
TLDR
A closer look at the optional matching feature of SPARQL, which allows the user to formulate queries which try to match parts of the query over the data if available, but do not destroy answers of the remaining query otherwise. Expand
Ontology-Enriched Query Answering on Relational Databases
We develop a flexible, open-source framework for query answering on relational databases by adopting methods and techniques from the Semantic Web community and the data exchange community, and weExpand
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