The W3C Semantic Web Activity has apparently found it necessary to publish yet another foundational technology for the semantic web, the Rule Interchange Format, "a family of rule interchange dialects that allows rules to be translated between rule languages and thus transferred between rule systems." Hmm, isn't this sort of semantic translation exactly what first RDF and then OWL were supposed to enable? I guess it's still turtles all the way up.
In any case there are now six working drafts:
"RIF Basic Logic Dialect" (BLD) specifies an XML format for rules at an intermediate expressive power. The language is roughly Horn rules with URIs, datatypes, and builtins. This goes beyond datalog (it has function terms), but does not provide any kind of negation. "RIF RDF and OWL Compatibility" explains and specifies how RIF rulesets are to be used in combination with RDF and OWL. Comments on these documents welcome until 19 September. In addition, RIF Production Rule Dialect (PRD) specifies an XML format for the exchange of production rules. PRD and BLD are expected to be the basis of the two main dialect-branches, with RIF Core being the things in common between the two. RIF Framework for Logic Dialects (FLD) and RIF Datatypes and Builtins (DTB) provide common elements for specific dialects to use. RIF Uses Cases and Requirements (UCR), last published about two years ago, has been simplified and now has examples written in the PRD and BLD presentation syntaxes.
