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Re: need to determine what RDF is

From: patrick hayes <phayes@ai.uwf.edu>
Date: Thu, 30 May 2002 15:57:01 -0500
Message-Id: <p05111a10b91c41af1883@[]>
To: "Seth Russell" <seth@robustai.net>
Cc: <www-rdf-comments@w3.org>

>I still fail to see why it is important for us to classify entailments. It's
>just going to over complicate stuff needlessly.  If my agent knows the rules
>for rdfs:subClass, than it can arrive at legitimate entailments,
>There is no universal overriding notion of 'legitimate' entailment,  is why.
>I agree it complicates things, but I see no way around the  fact that life
>is complicated.
>Life is complicated, agreed.  Consider the graph:
><ex:Jane> <rdf:type> <ex:Woman>.
><ex:Woman> <rdfs:subClassOf> <ex:Human>.
><rdfs:subClassOf> <rdfs:comment>  "Indicates membership of a class".
><rdfs:subClassOf> <ex:rule>  "(=> (subClass ?SUBCLASS ?CLASS) (forall
>(?INST)   (=> (rdf:type ?INST ?SUBCLASS) (rdf:type ?INST ?CLASS))))".
>Given that graph, do you agree that some agent could calucate that
>"<ex:Jane> <rdf:type> <ex:Human>."   ??

An RDFS-aware agent could, and that only requires the first two 
triples. The comments add nothing to the entailment.

>If so, then what kind of entailment is that, RDF, or RDFS, or is it EX, or
>is it RDF+EX+RDFS ?

RDFS (which includes RDF).

>  What are we to use that classification for?    In other
>words what is the actual utility of that kind of thinking?

The utility is that if I come across some published conclusions, I 
want to be able to find out what methods were used to arrive at those 
conclusions. If the thing that drew the conclusions advertises itself 
as an RDFS agent/reasoner, then I will be most upset if I find that 
it was using some inference method that is not RDFS valid. In fact, I 
might sue whoever wrote it for breach of contract and false 

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Received on Thursday, 30 May 2002 16:57:00 UTC

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