[SWC] update in embeddings and semantics of OWL compatibility

Dear all,

I finished all to do's related to the RDF and OWL compatibility document 
[1], with the exception of those that depend on the definition of the 
semantics of BLD, which is not yet finalized (I included markers to 
indicate which things will need to be changed).

The biggest changes are the new introduction to the OWL compatibility 
section, which no explains why there is a difference between the DL and 
Full semantics.
I also slightly changed the semantics of RIF-OWL DL compatibility so 
that classes and properties now interpreted differently from unary and 
binary predicates, so that it is still possible to use such predicates 
in RIF-OWL DL combinations.

Finally, I extended the embeddings appendix to embed also part of 
RIF-OWL DL combinations.  I identified a DLP subset and defined in the 
embedding of RIF-OWL DLP combinations into RIF.
Incidentally, this embedding uses negative guards (e.g., isNotString) 
for the embedding of ranges of datatype properties (guard predicates are 
not allowed to occur in rule heads, so instead of a positive guard in 
the head, we need a negative guard in the body).
The embedding is currently quite dry; I will add some explanatory text 
later on.


Best, Jos

[1] http://www.w3.org/2005/rules/wiki/SWC
-- 
                          debruijn@inf.unibz.it

Jos de Bruijn,        http://www.debruijn.net/
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