Re: InverseFunctional properties are the new URI?

Actually, I think I'll disagree with myself before anyone else does. 
Taking Dan's point, the ordering could well be IFP > no URI/IFP > URI 
because the URI is in no way a property of the described object whereas 
all other properties are.



Simon Price wrote:

> And, of course, IFP's may not be enough either in some circumstances. 
> For example, where descriptions are partial and non-overlapping or where 
> different (but both correct) IFPs are available in a pair of RDF 
> descriptions, then smushing becomes non-trivial.
> For hand-crafted RDF, it is likely that the author will provide nice 
> IFPs but for generated RDF (e.g from web mining) there may well be no 
> IFPs. So, really we have a sliding scale of convenience for smushing 
> RDF: URI > IFP > no URI/IFP. Hence, Dan's point about unrealistic 
> expectations about URIs in the early days could be extended to cover 
> IFPs at the present. A whole class of interesting applications of the 
> Semantic Web are likely to arise where smushing is required without 
> either URIs or IFPs.
> Cheers
> Simon
> Dan Brickley wrote:
>> * Phil Dawes <> [2004-07-29 17:52+0000]
>>> Hi All,
>>> I've noticed that some RDF specs (including FOAF and DOAP) use
>>> inverseFunctional properties instead of URIs to identify instance
>>> resources.
>>> I can see an instant benefit in doing this - end users don't need to
>>> worry about the problems of minting URIs, maintaining them etc..
>>> Is this the way RDF is going - URIs for the schema, BNodes with
>>> InverseFunctional properties for the instancedata?
>>> What are the consequences?
>> I think we'll always need both.
>> In FOAF I've tried to be pragmatic. When "what is 'the' URI for a
>> person" silliness was holding up deployment, FOAF encouraged an 
>> emphasis on reference-by-description techniques. OWL subsequently gave
>> us a way of expressing simple reference-by-description strategies in a 
>> machine readable way. But FOAF doesn't rule out the possibility of 
>> their being URIs for people, companies, etc. It just doesn't let the 
>> current lack of such things get in the way.
>> Rob McCool and Guha in their TAP work take a similar line, advocating 
>> reference-by-description as a useful strategy for merging Web data.
>> I think in the early days of RDF there was something of a fairytale
>> quality to the way URIs were perceived - basically a myth that all 
>> interesting and description-worthy things will have well-known URIs.
>> FOAF and reference-by-description in general shouldn't be taken as an
>> attack on URIs as such, but as advocacy that other techniques are 
>> useful too, and that we can write applications that figure out common 
>> references without all parties necessarily sharing the same URIs or 
>> even identifying expressions.
>> All that said, we've a long way to go before all RDF toolkits support 
>> InverseFunctional-based identity reasoning "out of the box"...
>> Dan


Simon Price, Technical Consultant, Internet Development Group
Institute for Learning and Research Technology

Received on Thursday, 29 July 2004 16:40:14 UTC