From: pat hayes (phayes@ai.uwf.edu)
Date: 05/29/01
>Hi, > >some additions to Pats suggestion: > >1) In many applications it is important to distinguish between >different kind of RDF data, eg. > the easiest example or different sources of RDF data, one is >trustworthy, the other one > not. That seems to me to be an assertion about the source rather than the data (?) But in any case it goes well beyond the RDF or DAML semantics. >This needs to be reflected in the rule language - it is not >sufficient to just query if a certain > fact is present. To distinguish between different sources would >be enabled by model identifiers > > subject[predicate->object]@model I have no idea what you are talking about. What is a 'model' in this sense? >It is also possible to allow operations on models, e.g. >intersection, union and setdifference. They sound like classes to me. >1) subject[predicate->object]@(mod1 intersect mod2) >2) subject[predicate->object]@(mod1 union mod2) >3) subject[predicate->object]@(mod1 \ mod2) > >1+2+3 are allowed in a rule body, only 1 is allowed in a conclusion >(this still allow to have a horn clause interpretation). > >Finally, for most applications it is also useful to allow skolem functions >as model identifiers, e.g. > >subject[predicate->object]@model(X) > >This allows parameterized models > >Furthermore: Full first order language bodies can be achieved by the >Lloyd-Topor Transformation, Can you give a pointer? I havnt heard of this. >provided >e.g. semantics for negation. Well-founded semantics is usually >regarded as the most suitable one - >especially in the case of RDF (just one predicate symbol). This idea of there being only one predicate symbol is a joke, right? Pat --------------------------------------------------------------------- IHMC (850)434 8903 home 40 South Alcaniz St. (850)202 4416 office Pensacola, FL 32501 (850)202 4440 fax phayes@ai.uwf.edu http://www.coginst.uwf.edu/~phayes
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