Re: rule proto-proposal

From: pat hayes (
Date: 05/29/01

>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 

>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.
>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.

>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?


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