Re: To embed or combine

> > <chair>
> > The status of the discussion regarding Jos' RDF compatibility section
> > appears to be mired in whether the normative semantics of RDF in RIF
> > should be specified in the model theory through a "combination" of RIF
> > and RDF semantics, or through an "embedding" of RDF semantics in RIF (as
> > rules).  The two approaches have been shown by Jos to be equivalent.
> 
> The two approaches are only equivalent with respect to entailment. If
> you want to extend either language (RDF for RIF), then they will differ.
> 
> > 
> > At the moment I have not seen any technical arguments supporting one
> > approach or the other. 
> 
> There are two main technical arguments for the model-theoretic approach:
> 
> i) It directly extends the RDF (as well as the RIF) model theoretic
> semantics, and is thus *by definition* faithful to the semantics.
> 
> ii) The approach is extensible, in the sense that it can be immediately
> used for any semantic extension of RIF (or RDF, for that matter), such
> as counting. The embedding of RDF in RIF would have to be reevaluated
> for most kinds of extensions of RIF, in order to make sure the
> entailments are the ones you might expect.

And your semantics will not need to be reevaluted for most kinds of
extensions of RIF & RDF? 


	--michael  


> Best, Jos
> 
> > Michael prefers the "embedding" on the basis that:
> > 
> > (1) the "combination" is more complicated than the "embedding" and thus
> > more difficult to understand.
> > 
> > (2) it is not our job viz. our charter to specify a model theoretic
> > approach to the RDF/RIF combination
> > 
> > Jos seems to prefer the "combination" and argues re: (1) that:
> > 
> > (3) it is no more difficult to understand the "combination" than the RIF
> > model theory.
> > 
> > As chair, my own read of the charter does not provide any particular
> > help on (2), I'm not quite sure what Michael is referring to there.  It
> > is certainly our job to specify how RIF and RDF should be used together,
> > and as chair I interpret this as meaning we should have a normative
> > standard for that.
> > 
> > Thus, as suggested by Michael, it seems to me we are at a difference in
> > preference only, and I see no alternative other than to call a vote.  It
> > seems to me the vote is about which approaches to make *normative*:
> > 
> > 1) The model-theoretic "combination" of RIF and RDF is normative
> > 2) The "embedding" of RDF semantics as RIF rules is normative
> > 3) Both the "combination" and "embedding" are normative (What would that
> > mean?)
> > </chair>
> > 
> > -Chris

Received on Monday, 10 September 2007 07:51:06 UTC