Example: Connecting the Dots
- a key goal of the Semantic Web is to aid in combining information
(statements) about specific instances from multiple sources
- RDF and DAML provide several mechanisms to accomplish this
- the following examples use the family of President George W. Bush,
using fictitious email addresses as URIs
- RDF implicitly collects statements about the same URI, e.g.
given the inputs
- RDF includes a concept of blank (anonymous) nodes that allow us to
refer to things by description, e.g.
Blank nodes can be merged.
allows us to explicitly link different URIs for the same instance,
- DAML ontology cardinality constraints
(particularly cardinality 1) can allow us to infer equivalence,
e.g. a Person has only 1 father so
can allow us to merge nodes based on a property value,
e.g. if emailAddress is unambiguous, then
- some inferences can't currently be expressed using DAML+OIL
due to their computational complexity exceeding the tractability
we might expect to infer
but we can't currently.
will be able to express such
inference rules, translation rules, etc.
- DAML Proof
will trace the inferences made, e.g.
we might conclude
with a proof like
- jenna sibling barbara
twin daml:subPropertyOf sibling
- barbara father georgew
because of the DAML Rules rule discussed above