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Re: when is a node a class, when is a node a shape, when is a node an instance of a class

From: Arthur Ryman <arthur.ryman@gmail.com>
Date: Thu, 28 Jan 2016 12:43:28 -0500
Message-ID: <CAApBiOmboW2qm6uN6VDSxUvvM8f+Sz507LKYj1wHzYV0wBCQRA@mail.gmail.com>
To: "Peter F. Patel-Schneider" <pfpschneider@gmail.com>
Cc: Holger Knublauch <holger@topquadrant.com>, "public-data-shapes-wg@w3.org" <public-data-shapes-wg@w3.org>
All,

This topic came up in ISSUE-23. I created ISSUE-120 to track this.

-- Arthur

On Fri, Jan 15, 2016 at 7:21 PM, Peter F. Patel-Schneider
<pfpschneider@gmail.com> wrote:
> My guess is that every place more than one triple might be involved needs this
> determination, given that it is no longer the case that all the triples needs
> to be in the data graph except for the determination whether a node is a shape
> (which is an exception to a more general notion, I guess).
>
> peter
>
>
> On 01/14/2016 08:16 PM, Holger Knublauch wrote:
>> On 15/01/2016 12:14 PM, Peter F. Patel-Schneider wrote:
>>> That is not sufficient because there are several sources of information input
>>> into SHACL.  For example, is a node an instance of a class for scoping if the
>>> rdf:type triple is in the shapes graph, or do only triples in the data graph
>>> count for this?
>>
>> Ok, these questions need to be answered on a case-to-case basis. For your
>> specific issue above (if I understand it correctly), I have added a clarifying
>> sentence to state that the triples must be in the data graph.
>>
>> https://github.com/w3c/data-shapes/commit/de401e2c411b616bb821fd7d313cebad0835d4c5
>>
>>
>> Which other places would require such clarifications?
>>
>> Thanks,
>> Holger
>>
>>
>>>
>>> peter
>>>
>>>
>>> On 01/14/2016 03:14 PM, Holger Knublauch wrote:
>>>> The spec currently has section 1.1 where we state that certain terms from RDFS
>>>> are used with slightly different meaning in the SHACL spec. Maybe, to satisfy
>>>> the issue you raise below, we could expand this section a little bit to
>>>> clarify that "being in instance" means something like
>>>>
>>>> ASK {
>>>>      $type rdfs:subClassOf* ?class .
>>>>      $instance a ?class .
>>>> }
>>>>
>>>> Then, "being a class" means $type=rdfs:Class and "being a shape" means
>>>> $type=sh:Shape.
>>>>
>>>> Would this help?
>>>>
>>>> Holger
>>>>
>>>>
>>>> On 15/01/2016 2:09 AM, Peter F. Patel-Schneider wrote:
>>>>> SHACL currently depends on the answers to several class-based questions,
>>>>> including
>>>>> - when is a node a class
>>>>> - when is a node a shape
>>>>> - when is a node an instance of a class
>>>>> but how these are determined is not completely spelled out in the SHACL
>>>>> documment.
>>>>>
>>>>> I think that there needs to be a complete definition of these
>>>>> relationships in
>>>>> the SHACL document and test cases to back up the definition.
>>>>>
>>>>> peter
>>>>>
>>>>
>>
>
Received on Thursday, 28 January 2016 17:43:56 UTC

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