[doap-interest] relating doap:homepage and foaf:homepage

[Dan Brickley]

Hi Edd,

(aside: the rdfs:domain of foaf:homepage was recently broadened from 
foaf:Agent to rdfs:Resource, ie, anything can in principle have a
homepage now).

If it's the case that anything that has a doap:homepage of X also has a
foaf:homepage of X, would you consider amending the DOAP schema 
at http://usefulinc.com/ns/doap to assert this? 

In passing, we probably shouldn't assert that anything with a foaf:homepage of Y
also has a doap:homepage of  Y, since that'd imply (per doap:homepage's
rdfs:domain of doap:Project) that it'd be a doap:Project, and there are
many non-Project things with foaf:homepage.

The addition would be 

  <rdfs:subPropertyOf rdf:resource="http://xmlns.com/foaf/0.1/homepage"/>

...this should btw let us share work on translations of comparable
schema terms :)

If you're ok with this, I could put corresponding statements into the
FOAF schema. 

A FAQ draft: 

	Q: Why does DOAP have its own property called doap:homepage 
	instead of using the existing and widely used foaf:homepage 
	property?

	A: doap:homepage has additional semantics; it is defined 
	as being applicable only to things that are in the doap:Project
	class (expressed using rdfs:domain in the DOAP schema). This 
	means that whenever you claim that some thing, let's call it X,
	has a doap:homepage of some thing, Y, you're implicitly 
	claiming that X is a doap:Project.

	    More generally, all RDF vocabularies encounter this 
	question: how self-contained should they be? The DOAP design tries 
	to find a middle ground between two extremes - it uses bits of 
	FOAF where relevant, but doesn't try to draw on dozens of 
	relevant but scattered RDF vocabularies.
	
Not wanting to put words into your mouth, of course. But that's my take
on the DOAP design tradeoffs...

cheers,

Dan

ps. see http://lists.w3.org/Archives/Public/public-esw/2004Sep/0004.html
http://rdfig.xmlhack.com/2004/09/23/2004-09-23.html#1095929014.190278
for more context (I'd like to show data merging between DOAP, FOAF and
SWED project descriptions...)

ps. OWL folks are urging me to drop the owl:import statements in the
FOAF schema, which I'll probably do at the next update, replacing them
with rdfs:seeAlso. You might want to consider doing the same. It's all
voodoo anyway and as far as I'm concerned rdfs:seeAlso was all I really
cared to assert!