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Re: regrets and a new spin on contexts

From: Pat Hayes <phayes@ihmc.us>
Date: Sat, 28 Apr 2012 22:08:21 -0500
Cc: public-rdf-wg@w3.org
Message-Id: <B7C67B2C-8082-4759-BF36-18E43324F51B@ihmc.us>
To: Antoine Zimmermann <antoine.zimmermann@emse.fr>
Sorry, I have been offline for a few days. I will tidy up and expand the wiki page ASAP, probably Monday.   In the meantime:

On Apr 25, 2012, at 9:02 AM, Antoine Zimmermann wrote:

> The semantics does not say to what syntax it applies. There are examples in TriG given, but does it mean that the semantics apply to RDF Datasets?

To the graphs in the dataset. However, I was using Sandro's convention for distinguishing between genuine graph names and mere dataset labels, and that needs the dataset syntax. 

> This proposal does not make explicit what is the satisfaction relation (the ⊨ symbol, \models in LaTeX

Thanks, but I am allergic to latex. 

> ) that relates interpretations to the theories in the logic that they satisfy. 

I was trying to avoid too much mathematical flimflammery, but I will write it out more exactly. 

> 
> It says: "the rest of the semantics (for triples, graphs, blank nodes, etc.) are exactly as in the 2004 semantic specifications"
> 
> but this is not enough. As an example, this is not sufficient to determine what happen to bnodes (especially bnodes that appear in different "named" graph).

The semantics applies to graphs, so the blank nodes really are exactly as in 2004. We could change this, of course, but that is orthogonal to this issue.  It uses the Trig machinery only to attach names to graphs, since these names now can play a stronger semantic role. 

> 
> There's also the term rdf:Graph used in one example but nothing is said about how it is interpreted in the model theory (but ok, it's just an example).
> 
> Yet anyway, with what's written I am able to extrapolate and what I see is essentially the same as my proposal in [1], on top of which the idea of "rdf:inherits" has been built.

Yes, it is partly based on your idea. It amounts to a generalization of it along the lines of the Cyc-Guha-McCarthy context logic. (I stated this explicitly in the earlier draft which uses the "context" terminology, see http://www.w3.org/2011/rdf-wg/wiki/RDFwithContexts#Two_current_ideas .) It differs in that it the rdf:inherits provides a way to distinguish between graphs being merely named and those being asserted in a "context". I think it is important to keep this as an option, as this allows both your kind of intended uses (with a small syntactic overhead, admittedly, which I think can be minimized) and those in which people strongly do not wish to contextually-isolate their IRIs. 

BTW, I intended this to be seen as as extension of your semantic idea, incorporating it into the RDF model itself. It changes the graph semantics so as to make a dataset (modified slightly using rdf:inherits and graph names) have your semantics as an option, that option being controlled by RDF content in the graphs. 

> 
> 
> 
> Also a side remark wrt the form: I would be happier if the semantics use
> "I ⊨ G" instead of "I(G) = true", as according to my experience, there is an overwhelming majority of authors in the knowledge representation field (especially semwebers) using the former and not the latter. It would also allow us to avoid introducing the unorthodox notion of "occurrence". But this may just be a question of taste.

I think this can be phrased to avoid the "occurrence" language, which I agree is awkward. Im working on it. 

Pat



> 
> 
> 
> [1] Dataset semantics. http://www.w3.org/2011/rdf-wg/wiki/TF-Graphs/RDF-Datasets-Proposal#Semantics
> 
> 
> 
> Le 23/04/2012 09:45, Pat Hayes a écrit :
>> First, regrets for next Wednesday, I will be driving through Texas.
>> Second, I have written up essentially the same proposal in a slightly
>> different terminology which might (?) be more palatable, anyway it is
>> there for inspection at
>> http://www.w3.org/2011/rdf-wg/wiki/AnotherSpin
>> 
>> Pat
>> 
>> ------------------------------------------------------------ IHMC
>> (850)434 8903 or (650)494 3973 40 South Alcaniz St.
>> (850)202 4416   office Pensacola                            (850)202
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>> 
>> 
>> 
>> 
>> 
>> 
>> 
> 
> -- 
> Antoine Zimmermann
> ISCOD / LSTI - Institut Henri Fayol
> École Nationale Supérieure des Mines de Saint-Étienne
> 158 cours Fauriel
> 42023 Saint-Étienne Cedex 2
> France
> Tél:+33(0)4 77 42 83 36
> Fax:+33(0)4 77 42 66 66
> http://zimmer.aprilfoolsreview.com/
> 
> 

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Received on Sunday, 29 April 2012 03:08:55 UTC

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