Picking up a thread from a couple of weeks ago...

On Aug 26, 2015, at 11:44 AM, Steven Folsom wrote:
> I noticed throughout this thread
> (and in the VIAF data) authority URIs being used as the objects of
> properties where instead person, places, etc. URIs should be. For
> example, (as previously
> mentioned) VIAF has separate URIs for the person and the authority,
> but then they go on to make a sameAs assertion between the VIAF
> *person* and an id.loc.gov *authority*. I hope this is just a mistake,
> and that they would be open to making the sameAs assertion between the
> VIAF foaf:Document and the id.loc.gov authority.

Here's a rationalization of VIAF's RDF treatment of *real-world entity* vs. *authority* ("sameAs" vs. "focus" vs. "identifiedBy", etc.)

- The VIAF URI (e.g. http://viaf.org/viaf/36997809) identifies the *real-world entity*
- To maximize cross-domain interoperability, VIAF uses Schema.org vocabulary as much as possible to describe the entity.
- E.g. http://bit.ly/1NKEvOa
- These VIAF entities are not dependent on preconceptions of "authority".
- VIAF entities use schema:sameAs rather than owl:sameAs/madsrdf:isIdentifiedBy to avoid splitting the entity/authority hair when linking to external URIs.
- The use of schema:sameAs "tends to blur distinctions which are important to OWL users, such as URIs for entities versus the pages that describe them". In VIAF's case, the blurring effect is between *entity* vs. *authority*. This blurring is intentional because most consumers of VIAF entities won't understand or care about the difference.
- http://www.w3.org/wiki/WebSchemas/sameAs
- For use cases that *do* understand and care about the entity/authority difference, VIAF uses foaf:focus instead of schema:sameAs in the reverse direction.
- E.g. http://bit.ly/1LInbWN
- Unlike the VIAF *entities*, which use Schema.org vocabulary to maximize cross-domain interoperability, these *authorities* are mainly described using SKOS.

Hopefully this outline clarifies some of the details behind VIAF's RDF. If not, I can try to elaborate.

Jeff