[rdfweb-dev] Time's running out?

Jim Ley jim at jibbering.com
Mon Aug 11 22:24:27 UTC 2003


"Julian Bond" <julian_bond at voidstar.com>
> Jim Ley <jim at jibbering.com> wrote:
> >My approach is to find all the THINGS with a  foaf:mbox_sha1sum and then
see
> >what those things know, doing it this we way can ignore the type in the
> >code, it does mean that we use data of the slightly less defined THINGS,
> >however because of the foaf:mbox_sha1sum limitation on it being about a
> >foaf:Person, we're not very limiting by just looking at THINGS, and it
means
> >people can use much neater syntax in their RDF docs, and I don't need to
> >teach my tools about subClasses.
>
> Trying to get my head round this. Look for mbox or mbox_sha1sum. Get
> their owner, then look at the other properties of that.
>
> Then I checked the spec to find that both mbox and mbox_sha1sum have
> domain and region "not specified". So where's the limitation on them
> being about foaf:Persons? Just a convention?

No, this is the broken current html documentation, in the RDF it says
mbox_sha1sum indicates it's an Agent (not a Person, a recent change, sorry
about that.)

  <rdfs:domain rdf:resource="http://xmlns.com/foaf/0.1/Agent" />

> Then we have foaf:knows which does have Domain and Region of
> foaf:Person. So if a file author is perverse enough not to use Person
> for the main data, they then shouldn't use knows to link that
> not-a-Person to other not-a-persons.

No, because you do not have to specify the type, consider the rdfs:seeAlso
property that has the domain of a rdf:Resource, does that mean you have to
specifically specify that it's a resource?  Remember everyone can have many
different type's  (they can be an Agent, a Person, a MalePerson, a
Programmer, a BridgePlayer, an Actor etc. etc.) so it would be crazy to make
people use different mbox properties depending on if you were talking about
someone as a BridgePlayer and a Programmer) e.g.

<brigeNS:Player>
 <bridgeNS:mbox_sha1sum>....</bridgeNS:mbox_sha1sum>
</bridgeNS:Player>

<progNS:Player>
 <progNS:sha1sumOfMbox>....</progNS:mbox_sha1sum>
</progNS:Player>

That isn't very helpful, teaching our tools that the sha1 properties are the
same, is a lot more work, and it hugely increases the number of predicates
we need to have.  Re-using namespaces is good.

An author is not Perverse not to use foaf:Person, there's lots of reasons
for them not to, and it makes no difference on their ability to use
foaf:knows.

Jim.




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