comment on RIF Working Drafts

Hi,


I am the head of the Database and Information Systems group at the 
University of Freiburg in Germany. We have been working with rule 
technologies since many years. We have been implementing full F-Logic 
and applied the resulting Florid system for data integration, web data 
extraction and for the implementation of workflows. We have learned that 
specifying rules with a certain semantics in mind and to evaluate them 
is not the same thing.  One has to observe that rule engines may have 
subtle differences in semantics even when syntax is identical. What has 
been missing for all the years is a layer of neutralization which makes 
it possible to clearly decide on the semantics of rule programs with 
respect to different rule languages and rule systems.

I am now glad to see that the RIF initiative was successful to fill 
exactly this gap. They cover the whole range of rule languages between 
those having a foundation in mathematical logic and those being based on 
the production rule paradigm. The evolution of the semantic web is given 
profound attention by clarifying the compatibility between ontologies 
based on RDF and OWL on one side and rule languages on the other.

I expect that the RIF Framework for Logic Dialects (RIF FLD) will 
amplify recent efforts on the integration of languages based on OWL 
using open world semantics with deductive rule languages using closed 
world semantics, as well as the efforts of the development of a logical 
basis for production rule languages. We are now motivated to investigate 
ways to built a rule language on top of SPARQL. I am convinced that RIF 
FLD will give us the needed framework to start.

The RIF working group is doing a great job and I wish them all the 
necessary support they need to continue their successful path.

Georg Lausen