Bipartite Graphs as Intermediate Model for RDF

RDF Graphs are sets of assertions in the form of subjectpredicate-object triples of information resources. Although for simple examples they can be understood intuitively as directed labeled graphs, this representation does not scale well for more complex cases, particularly regarding the central notion of connectivity of resources. We argue in this paper that there is need for an intermediate representation of RDF to enable the application of well-established methods from graph theory. We introduce the concept of RDF Bipartite Graph and show its advantages as intermediate model between the abstract triple syntax and data structures used by applications. In the light of this model we explore the issues of transformation costs, data/schemastructure, and the notion of RDF connectivity.