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Re: Deep copy

From: Peter F. Patel-Schneider <pfpschneider@gmail.com>
Date: Sat, 24 Sep 2016 14:35:03 -0700
To: Dimitris Kontokostas <kontokostas@informatik.uni-leipzig.de>
Cc: Holger Knublauch <holger@topquadrant.com>, "public-rdf-sha." <public-rdf-shapes@w3.org>
Message-ID: <07be4d55-54ee-11e1-8b90-ab1ab57a4690@gmail.com>
I'm assuming that you mean

The value of sh:path of each validation result must point to a SHACL property
path that is identical to the path provided in the constraint.

This is actually worse.  Identical is not defined at all in the SHACL document
and there is no pointer to an external meaning.  There is no useful guidance
to be found in the RDF documents either.  Falling back on general principles
would result in either identical nodes or identical graphs, both of which make
sense in an RDF setting, but neither of which are what is wanted here, I think.

The solution that is needed is to define a notion of equivalence/identicalness
for SHACL property paths.  The section on property paths needs a complete
rewrite anyway so defining identical/equivalent SHACL property paths can be
part of this needed change.

peter




On 09/24/2016 07:29 AM, Dimitris Kontokostas wrote:
> Thank you Peter,
> 
> can you check if the latest version has any issues?
> 
> Best,
> Dimitris
> 
> On Fri, Sep 23, 2016 at 8:36 PM, Peter F. Patel-Schneider
> <pfpschneider@gmail.com <mailto:pfpschneider@gmail.com>> wrote:
> 
>     Your reasoning is incorrect.
> 
>     It appears that what you mean by "deep copy" is somewhat related to its
>     meaning in LISP.  The meaning of "deep copy" that most readers will know of is
>     is meaning in current object-oriented languages, where all objects reachable
>     by inter-object links are copied.  This would end up copying the entire
>     portion of the RDF graph reachable from the head list node, which is not what
>     is desired here.
> 
> 
>     Peter F. Patel-Schneider
>     Nuance Communications
> 
> 
>     On 09/22/2016 10:38 PM, Holger Knublauch wrote:
>     > On 23/09/2016 11:36, Peter F. Patel-Schneider wrote:
>     >>
>     >>> Deep copy
>     >>>
>     >>> "a deep copy of sh:path as its sh:path" What is "deep copy" in this
>     >> context?
>     >>>      Comment (HK): I have attempted to clarify this here:
>     >>
>     https://github.com/w3c/data-shapes/commit/d3f8f858f95b010d1f2a0e4681da203bcbfbc217
>     <https://github.com/w3c/data-shapes/commit/d3f8f858f95b010d1f2a0e4681da203bcbfbc217>
>     >>
>     >>>      Comment (kc): Unless "deep copy" has some pre-defined meaning that I
>     >> am unaware of, I would suggest dropping it and saying: The value of sh:path
>     >> of each validation result must copy all triples that are required by the <a
>     >> href="#path-syntax">SHACL well-formed path syntax rules</a>from the
>     >> <a>shapes graph</a> into the graph containing the validation results.
>     >>>      Comment (HK): The first google match of "deep copy" is pretty
>     close to
>     >> what I wanted to express, so I believe the term should be familiar to many
>     >> people and may be helpful for implementers. Also I had surrounded the term
>     >> with "...". Anyway, I have no strong opinion and let others decide.
>     >>
>     >> The extra wording is helpful.  However, "deep copy" in
>     >> https://en.wikipedia.org/wiki/Object_copying#Deep_copy
>     <https://en.wikipedia.org/wiki/Object_copying#Deep_copy> is different.  Either
>     >> drop "deep copy" or point to an appropriate definition.
>     >
>     > Almost every English word is somehow overloaded with multiple meanings. I
>     > believe your linked deep copy is quite appropriate for what I am trying to
>     > express. If anyone has a suggestion on how to explain this better, please
>     > provide a complete replacement of the sentence - just dropping the term does
>     > not work.
>     >
>     > Thanks,
>     > Holger
>     >
> 
> 
> 
> 
> -- 
> Dimitris Kontokostas
> Department of Computer Science, University of Leipzig & DBpedia Association
> Projects: http://dbpedia.org, http://rdfunit.aksw.org, http://aligned-project.eu
> Homepage: http://aksw.org/DimitrisKontokostas
> Research Group: AKSW/KILT http://aksw.org/Groups/KILT
> 
Received on Saturday, 24 September 2016 21:35:36 UTC

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