Extending Shape Expressions for different types of knowledge graphs


Shape Expressions (ShEx) has been proposed as a concise and human-readable language to describe and validate RDF. Inspired by regular expressions, it offers an expressive formalism to describe graph structures based on regular bag expressions. Although plain RDF is one of the common data formats employed to represent knowledge graphs, there have been several proposals to either extend RDF with the so-called RDF-Star or RDF 1.2, or to employ other formalisms like property graphs. In this paper we present an overview and comparison of those approaches and propose three possible extensions of ShEx: ShEx-Star which can be used to validate RDF-Star, ShEx-N: that can be used when nodes also act as properties in RDF and PShEx, which can be used to describe property graphs. We present some examples and a semantics of each extension.

In 1st Workshop on Data Quality meets Machine Learning and Knowledge Graphs, DQMLKG, part of Extended Semantic Web Conference 2024, ESWC24.