November 29, 2019, 2:00 pm in room 3/124, Bt5
Title: Shape Expression Schemas Semantic, Complexity, and Inference
I will present continuing work on Shape Expression Schemas (ShEx) for RDF graphs, carried out in a number of collaborations. ShEx is a schema formalism inspired by XML schema formalisms, such as XML Schemas and DTDs, and the underlying tree automata models. Not surprisingly, ShEx can be seen as a model of graph automata, and interestingly, one that is related to the standard notion of graph simulation. First, we defined the semantics of ShEx and identify its computational implications on the problem of validation. Recently, we have been studying the problem of inference: given an RDF graph construct a ShEx that describes the structure of the input RDF. This study required us to address fundamental questions on containment of ShEx. Finally, I will outline future direction of study in repairing RDF w.r.t. a given ShEx.