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Re: Factoring of entailment regimes (was: Re: Ill-typed vs. inconsistent?)

From: Richard Cyganiak <richard@cyganiak.de>
Date: Fri, 16 Nov 2012 14:28:47 +0000
Cc: Pierre-Antoine Champin <pierre-antoine.champin@liris.cnrs.fr>, Antoine Zimmermann <antoine.zimmermann@emse.fr>, RDF Working Group WG <public-rdf-wg@w3.org>
Message-Id: <125733B9-3787-498D-AF32-42C0F5314024@cyganiak.de>
To: Pat Hayes <phayes@ihmc.us>
On 15 Nov 2012, at 21:29, Pat Hayes wrote:
> I like this ecept I'd like to keep the term "simple entailment" for the basic graph-level case, and so have this:
> 
> 1. SImple Entailment
> IRIs
> blank nodes
> triples
> graphs
> 
> 2. RDF with literals
> Datatype map
> Typed literals
> rdf:langString
> 
> 3. RDFS (including datatypes-as-classes, if you like: I agree might as well merge these.)

Okay, I guess Simple Entailment should be retained.

Just to be really clear here: I suppose this means that Simple Entailment would still say:

* if E is a language-tagged string "aaa"@ttt in V, then I(E) = <aaa, ttt>
* if E is a literal in V that is not a language-tagged string, then I(E) = IL(E)

Because that's essentially the translation of the current Simple Entailment conditions for literals to the new design.

And then RDF-with-literals Entailment would just add a single condition, something like (assuming we don't change the handling of ill-typed literals):

* if <aaa,x> is in D then for any literal "sss"^^ddd in V with I(ddd) = x , 
   if sss is in the lexical space of x then IL("sss"^^ddd) = L2V(x)(sss),
     otherwise IL("sss"^^ddd) is not in LV

So, technically speaking, rdf:langString would be handled in Simple Entailment, because that's the datatype that distinguishes language-tagged strings from other literals, and is the only datatype that isn't handled via the datatype map. 

(See here:
http://dvcs.w3.org/hg/rdf/raw-file/default/rdf-concepts/index.html#section-Graph-Literal
And the second note here:
http://dvcs.w3.org/hg/rdf/raw-file/default/rdf-concepts/index.html#section-Datatypes )

All the other conditions (starting to take the meaning of specific IRIs into account, other than the IRIs in the datatype map) would then be in RDFS-entailment.

That would work for me.

Background: This should make it possible to take the informative entailment rules out of Semantics, and put those for Simple Entailment and RDF-with-literals Entailment as an appendix into RDF Concepts, and those for RDFS Entailment into RDF Schema, each time with a clear statement that the normative form is the model theory found in RDF Semantics.

Best,
Richard
Received on Friday, 16 November 2012 14:29:18 GMT

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