Hi Tom,
The requirement of not hijacking existing formal specification languages for expressing constraints that rely on different semantics has not been raised yet.
In fact the discussions in the RDF-Shapes group showed that for a significant part of the RDF community, it doesn't matter. They just re-use the OWL syntax with closed world semantics.
I am not comfortable with it either, but ultimately we can't really overrun whatver the RDF Shape group decides to be acceptable.
I'd be in favour of raising it, but rather as an issue, or a desirable design principle, rather than a formal requirement.
Cheers,
Antoine
On 10/1/14 12:34 PM, Thomas Baker wrote:
> On Tue, Sep 30, 2014 at 11:05:08AM -0700, Karen Coyle wrote:
>> https://meetings.webex.com/collabs/meetings/playRecording?recordID=12797906&meetingInstanceID=ICWDUC9I93MGCE3CLXLPUZVPSX-JV0D
>
> I tried to join yesterday -- it was 23:00 here in Seoul -- but couldn't
> get a WebEx connection after five attempts. I did however get a chance
> to listen to the recording today. I'm sorry I couldn't be there live,
> because I'm trying to catch up with the discussion, and apologies in
> advance if the points I make have already been discussed and decided.
>
> Apart from the glitch that addresses do not know people, the DSP demo
> was very nice! However, I get very uneasy when I see OWL2 axioms being
> treated as "constraints" in a DSP sense (i.e., interpreted according to
> CWA). I agree with Karen, if I correctly understood her point, that
> this is "dangerous territory".
>
> On the call, that discussion was postponed for a later date, but I look
> forward to having that discussion as soon as possible because I think it
> is fundamental.
>
> As I see it, the whole question of how a constraint language relates to
> RDF vocabularies and ontologies is one of the most important and basic
> _requirements_ for the constraint language itself. The requirement is
> that a constraint language not replace (or "hijack") the original
> semantics of properties used in the data. I get uneasy, for example,
> when OWL cardinality axioms are treated as "constraints" according to a
> closed-world, unique-name assumption, or by using rdfs:domain or range
> axioms as if they were expressing mandatory graph patterns.
>
> In my recollection, the difference in meaning between "domain as a means
> of enabling inference" (the OWL sense) and "domain as a way to bind
> properties to classes" was a source of confusion when the Schema.org
> vocabulary first appeared, because the early, now-deprecated
> representations of the Schema.org vocabulary in OWL translated
> Schema.org domains as rdfs:domain, whereas the Schema.org data model now
> makes clear that a much looser definition is intended -- one that has
> more to do with documenting intention than with enabling inference [1]:
>
> We have a set of properties:
>
> each property may have one or more types as its domains. The
> property may be used for instances of any of these types.
>
> each property may have one or more types as its ranges. The
> value(s) of the property should be instances of at least one
> of these types.
>
> Has it been proposed to express as a requirement, alongside the other
> requirements, the notion that the constraint language not impose an
> alternative interpretation on existing semantics?
>
> Tom
>
> [1] http://wiki.dublincore.org/index.php/RDF-Application-Profiles/ExamplesFormalConstraints#R-25-OBJECT-PROPERTY-DOMAIN
> [2] http://schema.org/docs/datamodel.html
>
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