Re: mentionOf representation in RDF

Hi Graham,

My preference has always been to apply the QualifiedPattern to all prov 
relations, including this one,
but that's not the direction the group decided to follow.

Therefore the current solution is a compromise.

As far as your suggestion is concerned, see below some comment.


On 04/09/2013 10:29 AM, Graham Klyne wrote:
> Hi Luc,
>
> Just for the record, I'm OK with these changes.  I.e. no blockers.  
> But in the spirit of exploration, I'll pursue one of your responses a 
> little further...
>
> On 08/04/2013 22:24, Luc Moreau wrote:
>>  > Section 5
>>  >
>>  > I'm not understanding the motivation or purpose of the constraint
>>  >
>>  >    IF mentionOf(e, e1, b1) and mentionOf(e, e2, b2), THEN e1=e2 
>> and b1=b2.
>>  >
>>  > e.g. It seems to me that if bundle b1 has specializationOf(e1, e2) or
>>  > mentionOf(e1, e2, b2) then it would make sense for e to be a 
>> specialization of
>>  > distinct entities e1 and e2.
>>  >
>>  > Rather than just e1 = e2, is it not sufficient to allow:
>>  >
>>  >    specializationOf(e1,e2) OR specializationOf(e2,e1) OR e1 = e2
>>  >
>>  > ?
>>
>>
>> The reason for this constraint is the rdf encoding in two separate 
>> properties.
>>
>> With a ternary relation, we could express
>>   mentionOf(e, e1, b1) and  mentionOf(e, e2, b2).
>>
>> In rdf, we would have
>>   e prov:mentionOf e1
>>   e prov:asInBundle b1
>>   e prov:mentionOf e2
>>   e prov:asInBundle b2
>>
>> which would allow us to express
>>   mentionOf(e, e1, b2) and  mentionOf(e, e2, b1)
>> but nothing requires e1 to be described in b2 and e2 in b1.
>
> Ah, yes, I'd forgotten that aspect.  But I can't help wondering if 
> this is a case of the tail wagging the dog: designing semantics to fit 
> a particular syntactic pattern for a particular representation.
>
> An alternative RDF representation, arguably more in line with the 
> published best-practice note for dealing with n-tuples 
> (http://www.w3.org/TR/swbp-n-aryRelations/#pattern1), might be:
>
>   e prov:mentionOf
>     [ prov:specializationOf e1 ; prov:asInBundle b1 ] ,
>     [ prov:specializationOf e2 ; prov:asInBundle b2 ] .
>
> Or, equivalently:
>
>   e prov:mentionOf _:m1, _:m2 .
>   _:m1 prov:specializationOf e1 ; prov:asInBundle b1 .
>   _:m2 prov:specializationOf e2 ; prov:asInBundle b2 .
>
> Corresponding to
>
>   mentionOf(e, e1, b1)

You now have introduced a new resource _:m1, which is itself an entity.

So, for mentionOf(e, e1, b1),  we would have

    e, _:m1, e1, b1.

I am not sure what this _:m1 is.  How would you describe this entity?  
wht fixed
face does it have?

> mentionOf(e, e2, b2)
>
> where prov:mentionOf in the RDF might even be replaced with 
> prov:specializationOf, and prov:asInBundle with prov:has_provenance.
>
> (In constructing this example, I didn't set out to re-open the other 
> point I raised about the need for a new relation, but the introduction 
> of the extra RDF node here provides a place to hang the additional 
> aspect(s) associated with the two mentions.)
>

The additional node, as you suggest, is the right approach. But it is 
what the qualified pattern is already offering.
It would be awkward, in a same ontology, to have two different patterns 
to encode n-ary relations.

Luc

> #g
> -- 
>

-- 
Professor Luc Moreau
Electronics and Computer Science   tel:   +44 23 8059 4487
University of Southampton          fax:   +44 23 8059 2865
Southampton SO17 1BJ               email: l.moreau@ecs.soton.ac.uk
United Kingdom                     http://www.ecs.soton.ac.uk/~lavm

Received on Tuesday, 9 April 2013 11:08:58 UTC