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Re: rdfs:class and rdfs:resource

From: Francesco CannistrÓ <fracan@inwind.it>
Date: Sat, 10 May 2003 13:30:09 +0200
Message-ID: <03b901c316e7$8504da10$8d951d97@Matrix>
To: "Wolfram Conen" <conen@gmx.de>, <www-rdf-interest@w3.org>


with my previous post I wanted only to try to map your considerations to my
qeer metaphysical model in order to validate my meta-conclusions ;-)
However, it was only a sort of ontological game. The problem is old within
the philosophy of science: can an intuition theory or system be
ontologically free at all?
I do not know whether there is an acceptable answer to this question (and I
do not want to think about it anymore). I think only that, on the one hand,
metaphysically neutral criteria for inferences may be selected, but that, on
the other hand, these criteria cannot let infer judgements against the
engagement of metaphysical problems that may arise.
On my behalf, I have solved the problem with a politically correct "let it
I must precise that I have not considered the Model-Theory as axiomatically
formalized through LBase. This because I do not succeed in understanding
many things and I see there some incongruence. But this can be because I'm
not sympathetic with that formalization and I'm sure to commit many errors.
But now I think that it would be better to try to explain my perplexities
more rigorously, being concerned that, doing so, I risk to say many
stupidities :-)
I'll try to be clearer than I was in the previous rows, but I'm not sure
that  my English will let me do this.

The basic axioms of RDF  are:

(I) rdf:type(?x,?y) implies ?y(?x)
(II) rdf:Property(rdf:type)
The basic axioms of RDFS are:
(III) T(?x)
(IV) rdfs:Class(?y) implies (?y(?x) iff rdf:type(?x,?y))
(V) rdfs:Class(T)
(VI) rdfs:Class(rdfs:Class)

where T should be a synonym for rdfs:Resource.

I think we all agree that the following should be true:

(VII) rdf:type(?x, T)

But I do not succeed in understanding how  (I) and (V) can imply  (VII)
Neither I think that (I), (V) and (VI) imply that:

(VIII) rdf:type(rdfs:Class, rdfs:Class)

or that:

(IX) rdf:type(rdfs:Resource, rdfs:Class)

But I think we all agree that either (VIII) and (IX) should also be true as
If what I wrote is correct (is it???) there are problems (not paradoxes) and
incongruence with what we think that RDF/RDFS are and/or should be.

Therefore, I think that the real basic axioms of RDF should be:

(I) T(?x)
(II) rdf:type(?x, T)
(III) rdf:type(?x,?y) implies ?y(?x)
(IV) rdf:Property(rdf:type)

And RDFS axioms should be:

(V) T(?x)
(VI) rdfs:Class(?y) implies (?y(?x) iff rdf:type(?x,?y))
(VII) rdf:type(T, rdfs:Class)
(VIII) rdf:type(rdfs:Class, rdfs:Class)

Going back to the meaning of specs (not considering the LBase axiomatic
formulation of the Model Theory) I think that potential incongruence may
arise from the fact that "Resource" is tied to the RDFS namespace instead of
the RDF namespace. However, everything works fine if we assume that an
abstract concept of "Resource" exists that is not tied to RDFS and that RDFS
gives only a name to this concept.


----- Original Message -----
From: "Wolfram Conen" <conen@gmx.de>
To: "Francesco CannistrÓ" <fracan@inwind.it>; <www-rdf-interest@w3.org>
Sent: Friday, May 09, 2003 9:30 PM
Subject: Re: rdfs:class and rdfs:resource

> Francesco,
> I was trying to figure out, if the concept "class", as I understand it's
> in RDFS, makes much sense to me. So, I contrasted it to a view that would
> at least "distinguishable" from a concept "resource" (the view that, given
> resource that occurs as the object of a type statement, has a non-empty
> extension, and might therefore be called "class" with some justifiable
> motivation) (so, of course, my "axiom" (I) had to be taken from RDF, or
> otherwise there would have been no basis for the comparison ;-).
> I think you are aiming at a different problem? You saw the potential of a
> paradoxical situation arising from metaphysical consideration, if I
> that correctly?  Maybe you try to re-word your claim for the meta-physical
> lay person that I am?
> Best
>     Wolfram
> [PS: The concept "resource" in RDF, what does it convey?]
> ----- Original Message -----
> From: "Francesco CannistrÓ" <fracan@inwind.it>
> To: "Dr. Wolfram Conen" <conen@gmx.de>; <www-rdf-interest@w3.org>
> Sent: Friday, May 09, 2003 6:40 PM
> Subject: Re: rdfs:class and rdfs:resource
> >
> > Wolfram,
> >
> > your latest comments are excellent and perfectly "in topic" with my
> > But I want to let you note what follows:
> > 1) your axiom (I) is already assumed (at least implicitly) within the
> > spec;
> > 2) RDF Schema is an application of RDF [necessarily part of this???]
> > therefore, it must imports all RDF's assumptions.
> > In conclusion:
> > 3) the concept of "Resource" is not (neither could be) introduced by RDF
> > Schema,
> > 4) RDF Schema just captures this concept giving to it a name and then,
> once
> > introduced a set of concepts (among which that one of rdfs:Class) by
> > leveraging the innate concept of "Resource" as suggested by RDF,
> > the innate concept of "Resource" within the conceptual world it created
> > (assertig that rdfs:Resource is of type rdfs:Class).
> >
> > do you agree with me?
> >
> > Francesco
Received on Saturday, 10 May 2003 07:30:24 UTC

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