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Re: three kinds of dataset

From: Antoine Zimmermann <antoine.zimmermann@emse.fr>
Date: Wed, 07 Mar 2012 13:55:05 +0100
Message-ID: <4F575AA9.1050804@emse.fr>
To: "Peter F. Patel-Schneider" <pfpschneider@gmail.com>
CC: public-rdf-wg@w3.org

Infinity does not cause problems at all, on the contrary, that's why I'd 
like to allow dataset-interpretations to assign a "local" interpretation 
to an infinity of "graph names". Moreover, I'd like literals to be 
allowed as "graph names".

The reason is the following. Imagine I want to extend this weak 
semantics to a temporal semantics.

I'd like to say things like:

"[1927,1945]"^^interval { :x  a  :Child .}
"[1999,+\infinity]"^^interval { :x  a  :DeadPerson .}

and I want to infer that at any given year <y> >= 1999

"[<y>,<y>]"^^interval { :x  a  :DeadPerson .}

which requires that there exists an RDF/RDFS/etc-interpretation 
Con("[<y>,<y>]"^^interval) for any <y>.


Le 06/03/2012 19:31, Peter F. Patel-Schneider a écrit :
> Well, I don't see where the infinity causes problems.  RDF datasets and
> RDF graphs are going to be finite, after all, aren't they?  Perhaps for
> mathematical cleanliness you might want to allow interpretations to have
> an infinite number of names, I suppose.
> The wiki seems to be missing the notion that Con(V) is an interpretation
> of the graph with name V.
> In any case, the two formulations appear to be quite close (modulo the
> issue just above).
> peter
> From: Antoine Zimmermann<antoine.zimmermann@emse.fr>
> Subject: Re: three kinds of dataset
> Date: Tue, 06 Mar 2012 19:10:36 +0100
>> Why not indeed?  This was my original idea, modulo a little improper
>> formulation (you can see the previous version in the wiki) but 1) Pat
>> was very much against this formulation, and 2) the current formulation
>> allows a dataset-interpretation to assign a "local" interpretation to a
>> potentially infinite set of terms. This is particularly useful for
>> reasoning with annotated triples (UC 6.2 in
>> http://www.w3.org/2011/rdf-wg/wiki/TF-Graphs-UC#.28B_priority.29_Reasoning_over_annotations).
>> Le 06/03/2012 18:52, Peter F. Patel-Schneider a écrit :
>>> Why not just say that an RDF/RDFS/... dataset interpretation of
>>> 	D = (G, {<n1,G1>, ...,<nk,Gk>})
>>> is a structure
>>> 	I = (I, {<m1,I1>, ...,<mh,Ih>})
>>> where I is an RDF/RDFS/... interpretation of G
>>> and for each 1<=i<=k there is a j, 1<=j<=h such that mj=ni
>>> and Ij is an RDF/RDFS/... interpretation of Gi
>>> (could also require ni distinct and h=k)
>>> Then	D = (G, {<n1,G1>, ...,<nk,Gk>})
>>> entails D' = (G', {<n'1,G'1>, ...,<n'k',G'k'>})
>>> just when every RDF/RDFS/... datatset interpretation of D
>>> is also an RDF/RDFS/... datatset interpretation of G'
>>> peter

Antoine Zimmermann
ISCOD / LSTI - Institut Henri Fayol
École Nationale Supérieure des Mines de Saint-Étienne
158 cours Fauriel
42023 Saint-Étienne Cedex 2
Tél:+33(0)4 77 42 83 36
Fax:+33(0)4 77 42 66 66
Received on Wednesday, 7 March 2012 12:55:18 GMT

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