131 (155)
Rules
- OWL can be used for simple inferences
- Applications may want to express domain-specific knowledge, e.g.:
- (prem-1 ∧ prem-2 ∧ …) ⇒ (concl-1 ∧ concl-2 ∧ …)
- e.g.: for any «X», «Y» and «Z»:
- “if «Y» is a parent of «X», and «Z» is a brother of «Y» then «Z» is the uncle of «X»”
- “if «Y» is a parent of «X», and «Z» is a brother of «Y»
- then «Z» is the uncle of «X»”
- using a logic formalism (Horn clauses):
-
∀x,z: ((∃y: (y parent x) ∧ (y brother z)) ⇒ (z uncle x))
- Lots of research is happening to extend RDF/OWL
-
(Metalog,
RuleML,
SWRL,
cwm, …)
- Remember ℘Ω(ℛ(RDFS,OWL),Ω)?
- rules may help to develop such patterns, too
- W3C holds a workshop in April 2005
- the W3C way to explore possible standardization …
Current and Future Developments