Search Results for author:
Found 9 papers, 2 papers with code
Semi-Oblivious Chase Termination for Linear Existential Rules: An Experimental Study
In this work, we focus on the semi-oblivious version of the chase, which is well-suited for practical implementations, and linear existential rules, a central class of constraints with several applications.
The Complexity of Why-Provenance for Datalog Queries
Towards this end, we pinpoint the data complexity of why-provenance for Datalog queries and key subclasses thereof.
Absolute Expressiveness of Subgraph-based Centrality Measures
In graph-based applications, a common task is to pinpoint the most important or ``central'' vertex in a (directed or undirected) graph, or rank the vertices of a graph according to their importance.
Non-Uniformly Terminating Chase: Size and Complexity
In this context, a key problem is non-uniform chase termination: does the chase of a database w. r. t.
First-Order Rewritability of Frontier-Guarded Ontology-Mediated Queries
In both approaches, we provide semantic characterizations of FO-rewritability that are of independent interest.
When is Ontology-Mediated Querying Efficient?
We further study the complexity of the meta problem of deciding whether a given OMQ is equivalent to an OMQ of bounded tree width, providing several completeness results that range from NP to 2ExpTime, depending on the DL used.
The Limits of Efficiency for Open- and Closed-World Query Evaluation Under Guarded TGDs
For querying in the presence of constraints, we consider classes of constraint-query specifications (CQSs) that bundle a set of constraints with an actual query.
The Space-Efficient Core of Vadalog
Vadalog is a system for performing complex reasoning tasks such as those required in advanced knowledge graphs.
Containment for Rule-Based Ontology-Mediated Queries
We also apply our techniques to pinpoint the complexity of problems associated with two emerging applications of OMQ containment: distribution over components and UCQ rewritability of OMQs.
