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Re: example of recursive shapes

From: Peter F. Patel-Schneider <pfpschneider@gmail.com>
Date: Sat, 24 Jan 2015 18:33:01 -0800
Message-ID: <54C455DD.40107@gmail.com>
To: Holger Knublauch <holger@topquadrant.com>, public-data-shapes-wg@w3.org
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I still don't see how LDOM can handle this example if it is all supposed to
be translatable into SPARQL queries.  Perhaps a definition of LDOM will make
this clear, but I don't think that one has been presented as of yet.

peter


On 01/24/2015 06:23 PM, Holger Knublauch wrote:
> On 1/25/2015 11:48, Peter F. Patel-Schneider wrote:
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>> 
>> I can't tell whether this does or not, as there appears to be a missing
>> bit after ldom:predicate.
> 
> Ok, the missing bit was a left-over from when I noticed that we don't
> have a better syntax for owl:hasValue. I have meanwhile added a new
> template using ldom:hasValue to improve readability (not that it matters
> for the recursion though):
> 
> ex:Polentoni a rdfs:Class ; # or ldom:Shape, or nothing ldom:property [ 
> ldom:predicate ex:livesIn ; ldom:hasValue ex:NorthernItaly ; ] ; 
> ldom:constraint [ a ldom:ShapeConstraint ; ldom:predicate ex:knows ; 
> ldom:all ex:Polentoni ; ] .
> 
>> However, I don't think that it could, as least so far as I understand
>> LDOM, as the class definition below appears to require that
>> ex:Polentoni is asserted on some individuals, and the point of the 
>> example is that there are no assertions involving ex:Polentoni in the
>> input.
> 
> No, this is a misunderstanding. When ldom:all is used, it will simply
> check whether the instance matches all conditions specified by the given 
> class/shape. The rdf:type triple is not restricted by the shape,
> therefore no rdf:type needs to be present on the valid instances.
> 
>> 
>> If LDOM does work by doing recognition, then this should be
>> highlighted.
> 
> I have added a sentence
> 
> Note that the matching values do not have to be instances of the given
> shape, i.e. no <code>rdf:type</code> triple is required.
> 
> Needless to say the overall specification needs work to clarify and
> better explain these details - some of them are currently well hidden in
> the implementation (Turtle code/SPARQL queries).
> 
> HTH and thanks for the example. I hope we agree recursion is covered. 
> Holger
> 
> 
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Received on Sunday, 25 January 2015 02:33:36 UTC

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