Time and Date: 05:00 PM -- 06:30 PM, Monday, 19th Dec.

Title: Graph Queries: Do We Study What Matters?

Abstract：

Graph queries are studied extensively by many communities: data management, AI, Semantic Web. The development of the theoretical models of such queries happened in between the two eras of prominence of graphs: the early network data model (later overridden by relational) and more recent models of RDF and especially property graphs, gaining prominence in the last decade. Classical theory gives us the fundamental notion of Regular Path Queries (RPQ) and its many derivatives: CRPQs, UCRPQs, 2UCRPQs, ECRPQs, RDPQs, GXPath etc. This is still the model that dominates in research literature. Applications follow a different path however. A number of successful graph query languages including Cypher, PGQL, and GSQL led to the development of a new international standard called GQL (Graph Query Language). The core of GQL is loosely inspired by theoretical developments such as RPQs and GXPath. GQL is still work in progress and even when finished it will come in the shape of hundreds of pages of specs, rather than a simple definition in the spirit of relational calculus and algebra. This talk has three main objectives. First, it outlines the history of the development of graph query languages from the academic standpoint. Second, it presents an overview of pattern matching facilities of soon to be standardized GQL and its SQL counterpart called SQL/PGQ. Third, it proposes a simple definition of a pattern matching calculus that captures the essence of GQL and SQL/PGQ and suggests using it as the basis for further research.

Short bio:

Leonid Libkin is a professor of computer science at the University of Edinburgh and query language researcher at RelationalAI; he is also affiliated with École Normale Supérieure in Paris. He was previously scientific advisor to Neo4j, professor at the University of Toronto, and member of research staff at Bell Laboratories in Murray Hill. His main research interests are in the areas of data management and logic in computer science. He has written five books and over 250 technical papers. His awards include a Marie Curie Chair Award, a Royal Society Wolfson Research Merit Award, and six Best Paper Awards. He has chaired program committees of major database and logic conferences (PODS, LICS, ICDT), served as chair of the 2010 Federated Logic Conference and general chair of PODS. He is an ACM fellow, a fellow of the Royal Society of Edinburgh, and a member of Academia Europaea.