When two nodes in the central Graph are linked together by a line this indicates that they share a relationship. The nature of this relationship is represented as an Edge.
RDF-syntax distinguishes between the visual representation of a relationship in a graph and the textual representation as it is encoded in XML. The term "Edge" refers exclusively to graphs, while the term "Predicate" refers to a relationship as it is expressed through a Subject-Predicate-Object RDF triple-statement.
In this case, Augusta Ada Byron is connected to Lord Byron by the Edge hasFather.
This is a visual representation of the RDF triple statement: <Byron, Augusta Ada> <hasFather> <LordByron>.
