Some Comments on RIF BLD from an external reviewer

As a privacy protection and digital rights management policy researcher, I
am happy to see RIF working group delivers the RIF BLD (Basic Logic Dialect)
working draft (http://www.w3.org/TR/rif-bld/ ) and other related working
drafts, such as RIF Framework for Logic Dialects (FLD) and RIF RDF and OWL
Compatibility. This indicates an important step for standardizing the rule
exchange language for semantic web technologies and related applications.
After quick examing the RIF BLD working draft, I would like to provide some
comments that need to be clarified:


   1. Do we need to webize the  terms from rule module as well as ontology
   module in the RIF BLD? This webizing issue for both condition language and
   rule language can be further enhanced in the near future. For example, in
   EBNF grammar, it does have IRI (extension of URI) to refer to the original
   sources of FORMULA and ATOMIC terms. The naming prefix in the document/group
   preamble also provides the rule modules import sources. But it is quite
   possible some of imported terms in both the condition language and the rule
   language might come from ontology modules specified as RDF(S) and OWL
   ontology langauge. In that case, these terms and expressions might need to
   be webized. I am wondering whehter RIF BLD spec. itself already has this
   capacity to declare and webize the ontology related terms? Maybe, we can
   refer to the RIF RDF and OWL compatibility working draft to resolve this
   issue (I check this draft and it only very briefly discuss in section 5). On
   the other hand, we might said this is a rule interchange specification so we
   do not have to consider webizing the terms from ontology. But both condition
   langauge and rule language do have member and subclass terms in their
   respective EBNF grammar, I am not quite sure how these terms will be applied
   in the rule language expression because the membership and subclass term
   relationships usually happen in the ontology schema. Therefore, this also
   reflects the necessarity of webizing ontology terms in the condition/rule
   language.
   2. Does the RIF-BLD provides the power to resolve the semantics
   discrepancy from underlying different logic program-based rule systems? As
   mentioned in RIF BLD working draft 1 overview, for those people who need a
   direct path to implement but are not interested in extensibility issues,
   they choose RIF-BLD. Otherwise, they choose  a specifialization of the
   RIF-FLD. In this case, I am not sure whether RIF-BLD might be quite limited
   when we need to consider a variety of rule systems which might have the
   expressive power beyond RIF-BLD. The decision for people to choose RIF-BLD
   or RIF-FLD might need to be more clear and specific in the working draft.
   For example, if one rule interchange system is based on RIF-BLD and another
   rule interchange system is based on a specialization of extensible RIF-FLD,
   can those respecitve underlying rule systems with RIF-BLD and RIF-FLD as the
   RIF language in their hub centers and interchange their rule modules without
   worrying any semantic ambiquity problem after integration?

Overall speaking, all of RIF-BLD and related working drafts do consider the
semantic web cutting edge technology and development status and I am
expecting these RIF standards can be finialized in a near future.

-- 
Prof. (Dr.) Yuh-Jong Hu
(http://www.cs.nccu.edu.tw/~jong)
Emerging Network Technologies (ENT) Lab.
(http://sw.cs.nccu.edu.tw)
Dept. of Computer Science
National Chengchi University
Taipei, Taiwan.