[rdfweb-dev] PPD, revisited
ldodds at ingenta.com
Mon Feb 9 14:07:35 UTC 2004
The PPD thread seems (at least to me) to be wondering
off topic, so I'm hoping we can refocus the discussion
back on the 2 proposals on the table:
Morten pointed out that documents with multiple topics are
quite rare and so this seems redundant. An editor can just
check the foaf:topic of a document, if it's a foaf:Person, then
However foaf:topic isn't constrained in any way, so it's
legal to have multiple topics for a document. The above
method is therefore not fool-proof in the long term.
If foaf:topic were constrained, then we'd be good to go.
So that ought to be considered as well.
However I personally believe it's a useful feature, independent of
the "who is this document about?" use case, to be able to determine
the primary topic of a document. And for this reason I'd
prefer to see a new property defined for this purpose.
I'm in favour of this because of the facility to type rdfs:seeAlso
A scutter or FOAF explorer is then given an expectation of
what will be in the RDF graph resulting from traversing that
link. We already have specific expectations of what data
may in a graph when we fish about in it for specific properties.
I don't think this is any different.
Again, like foaf:primaryTopic I think this is a Good Thing
even independent of the of "who is this document about?"
It would follow naturally that the foaf:primaryTopic of a
PPD is a foaf:Person. But there's no limitation on what
triples may be in the data, nor constraints on syntax,
so I don't think that syntax vs. model is a concern.
Yes, someone could extend PPD and define a syntax
constrained version, but that's not be proposed currently.
Whether thats a good idea or not is a separate debate.
Yes, someone can have multiple PPDs. Having an extra
document class doesn't restrict that and usual smushing
rules can apply to merge data. Trusting the origin of the
data, and what that trust may be predicated on, is an separate
Yes, someone can author (foaf:made) a PPD on behalf of
someone else. That's why we have separate maker and
(primaryTopic|topic) properties so we can distinguish these
Use Case? The RDF web is only going to get larger,
therefore scutters, like HTML spiders, are going to have to
optimise their search paths through this web. Having an
extra type of foaf:Document will facilitate that.
Both of the proposals stand on their own merits, in addition
to serving the "who is this FOAF about?" use case. Why not
More information about the foaf-dev