Re: temporary urn:predicates

On Tue, Jun 30, 2015 at 9:03 AM, Melvin Carvalho <melvincarvalho@gmail.com>
wrote:

>
>
> On 30 June 2015 at 16:59, Melvin Carvalho <melvincarvalho@gmail.com>
> wrote:
>
>> I was talking recently about barriers to producing semantic web data.
>>
>> Normally a predicate has to be
>>
>> - A URI
>> - Preferably an HTTP URI
>> - Preferably an existing URI
>>
>> This (Im told) can be a barrier for newcomers.  They have to find the
>> right name for a predicate, the right URI, and then see if it's already
>> used.  If not create their own vocabulary.
>>
>> At this point some might give up.
>>
>> So I was wondering how it might be possible to create a temporary URI
>> that people could use as a place holder, so the software still works, until
>> they think of a better name.
>>
>> We've all had to do this at some point, right?
>>
>> So I originally used to use things like:
>>
>> </predicate> or
>> <#predicate>
>>
>> But that breaks down when you start using multiple documents because the
>> URI is relative to the base.
>>
>> So I thought why not use:
>>
>> <urn:predicate>
>>
>> It seems to me local predicates are "just a name" and a urn is "just a
>> name" so it would be a good match.
>>
>> My main concern is whether it would have collisions with the IANA
>> registry:
>>
>> http://www.iana.org/assignments/urn-namespaces/urn-namespaces.xml
>>
>> Any thoughts?
>>
>
> Someone pointed me to :
>
> http://www.w3.org/ns/activitystreams
>
> Which uses
>
> @vocab = _:
>
> So then
>
> predicate becomes _:predicate
>
> Maybe that's the right pattern ...
>
>
The only problem here is that predicates cannot be bnodes, they must be
URIs (in all versions of RDF, at least). (I'm assuming that's a bnode,
because that's most certainly not a valid URI or URI prefix.)

And even if they could, the semantics of bnodes would provide some pretty
funny conclusions.

Austin Wright.