What’s in a Neighborhood? Describing Nodes in RDF Graphs Using Shapes

There are several situations where it is desirable to be able to extract a subgraph from an RDF graph, based on a node in the graph, and given a shape that the node conforms to. Such a subgraph can be called a neighborhood. We discuss desiderata for neighborhoods, and compare different possible definitions. We show connections with data provenance and causality. We also show how to obtain provenance polynomials for the shape constraint language SHACL from the work of Dannert and Grädel.