Re: Terminology: How to call "IRI or blank node"?

A requirement for a URI for non-literal resources?  Is there a story that 
needs them?


peter


On 12/20/2014 09:11 AM, Karen Coyle wrote:
> I was using that facetiously (which doesn't come across well in email, I know.)
>
> But, rather than picking at nits, can we agree that we have a requirement, or
> no? And if no, what would be the reason?
>
> kc
>
> On 12/20/14 8:24 AM, Peter F. Patel-Schneider wrote:
>> No, we definitely do not have any story that is even vaguely related to
>> this issue.
>>
>> Story S1
>> https://www.w3.org/2014/data-shapes/wiki/User_Stories#S1:_The_model.27s_Broken.21
>>
>> is instead about missing information in an RDF graph that defines an
>> ontology.
>>
>> peter
>>
>>
>> On 12/20/2014 07:51 AM, Karen Coyle wrote:
>>> As we are here defining requirements that meet actual needs, don't we
>>> now have
>>> a requirement to include in the shapes or validation solution the
>>> ability to
>>> define an object type that excludes literal values? (Assuming others
>>> also find
>>> this requirement compelling.) Later we can determine whether/how that
>>> can be
>>> done. If it cannot be done with RDF, then I would hope that actual
>>> user needs
>>> are taken into account in RDF development, which I assume is not
>>> frozen at
>>> this point in time. If it cannot be done with RDF now or ever, then we
>>> are
>>> back to "The Model's Broken!" which is already one of our stories.
>>>
>>> kc
>>>
>>> On 12/20/14 7:12 AM, Peter F. Patel-Schneider wrote:
>>>>
>>>>
>>>> On 12/19/2014 11:36 PM, Holger Knublauch wrote:
>>>>>
>>>>> On 12/20/14, 4:33 PM, Eric Prud'hommeaux wrote:
>>>>>>
>>>>>> > We need a URI for that, so that we can say that "every value of a
>>>>>> given
>>>>>> property must be a resource". Basically a way to say "anything that
>>>>>> can
>>>>>> appear as a subject in a triple (and therefore can have its own
>>>>>> properties).
>>>>>> We have always used rdfs:Resource for that and it worked well in
>>>>>> practice -
>>>>>> and rdfs:Literal to say "every datatype". rdfs:NonLiteral does not
>>>>>> exist.
>>>>>> OWL had owl:ObjectProperty and owl:DatatypeProperty, and if you left
>>>>>> their
>>>>>> range empty then they had that default interpretation. How was this
>>>>>> ever
>>>>>> supposed to work in RDF Schema?
>>>>>>
>>>>>> RDFS never needed to address this distinction (arguably because it's
>>>>>> not s
>>>>>> schema language). It is certainly better to mint a new term than to
>>>>>> confuse
>>>>>> the meaning of an existing term.
>>>>>>
>>>>>
>>>>> I would be OK with a different term but this should then become the
>>>>> superclass
>>>>> of all other classes, so that the inheritance model is consistent.
>>>>> Currently
>>>>> only rdfs:Resource can play this role I think, but that unfortunately
>>>>> includes
>>>>> literals. And owl:Thing would suck in way too much complexity just for
>>>>> this
>>>>> technical detail (and existing models that use rdfs:subClassOf
>>>>> rdfs:Resource
>>>>> would be excluded too).
>>>>>
>>>>> Holger
>>>>>
>>>>>
>>>>
>>>> It appears that you are asking for the class whose instances are all
>>>> resources excluding literal values.  The expressive power required for
>>>> this class goes well beyond the bounds of RDFS.
>>>>
>>>> This new class cannot be the superclass of all classes.  It is not a
>>>> superclass of the class that is the fixed meaning of rdfs:Resource, of
>>>> course, and it is also not a superclass of class that is the fixed
>>>> meaning of rdfs:Literal or of any of the datatype classes.  Making this
>>>> class a superclass of all classes would break RDFS.
>>>>
>>>> It would also not be the case that the meaning of all IRIs and blank
>>>> nodes would belong to this new classes.  In RDF the meaning of an IRI or
>>>> a blank node can be a literal value.
>>>>
>>>>
>>>> peter
>>>>
>>>>
>>>
>>
>

Received on Sunday, 21 December 2014 00:32:41 UTC