Many modern companies wish to maintain knowledge in the form of a corporate knowledge
graph and to use and manage this knowledge via a knowledge graph management system …

Abstract Information systems have to deal with an increasing amount of data that is
heterogeneous, unstructured, or incomplete. In order to align and complete data, systems …

The chase algorithm is a fundamental tool for query evaluation and for testing query
containment under tuple-generating dependencies (TGDs) and equality-generating …

Over the past years, there has been a resurgence of Datalog-based systems in the database
community as well as in industry. In this context, it has been recognized that to handle the …

Ontology-based data access is concerned with querying incomplete data sources in the
presence of domain-specific knowledge provided by an ontology. A central notion in this …

The introduction of novel Datalog+/-fragments with good theoretical properties, together with
the growing use of enterprise knowledge graphs motivated the development of Vadalog, a …

Adopting a mature AI strategy is fundamental for modern knowledge companies to govern
the proliferation of smart AI-driven applications and to coordinate them within coherent …

A robust system for ontology-based data access should provide meaningful answers to
queries even when the data conflicts with the ontology. This can be accomplished by …

Ontological queries are evaluated against a knowledge base consisting of an extensional
database and an ontology (ie, a set of logical assertions and constraints that derive new …

We give a solution to the succinctness problem for the size of first-order rewritings of
conjunctive queries in ontology-based data access with ontology languages such as OWL 2 …