Databases: semistructured data, XML, data provenance, programming language interfaces, query languages, data models, knowledge bases, database semantics, user interfaces, distributed databases, database monitoring.

Programming languages: database interfaces, applicative and functional languages, type systems, implementation techniques, semantics.

General: mathematical phylogeny, neural models, cognitive science, data structures, graph theory, combinatorics, applications of computers in the humanities.

Database theory and systems.

Databases: query languages; relational, XML, and graph data; constraints and design; data integration and exchange; incomplete information.

Other topics: Logic in computer science, finite model theory, automata theory.

In the past: lattice theory, with some applications to programming semantics.

Database theory and practice, with a strong emphasis on making theoretical results applicable in real-life systems.

Current focus on devising and implementing principled and practical solutions for dealing with incomplete information in relational database systems, and on the analysis of concrete query languages for graph databases.

Database theory with emphasis on query languages, knowledge representation and reasoning, computational logic and its applications to computer science.

Bounded query processing, querying graph data.

Databases and large-scale data management systems: in-database learning, stream processing, incremental computation, query compilation.

Similarity query processing, query autocompletion, data mining.

Consistent query answering.

Incomplete information in relational databases.

Query optimization and intermediate results recycling in relational databases.

Consistent query answering.

Databases: query languages, relational and graph data, incomplete information. Logic in computer science; automata theory; game theoretic aspects of blockchains.

Parallel query processing.

Approximate query processing.

Incremental graph computation.

Fraud detection.

Data quality, database system optimization, machine learning.