[rdfweb-dev] Re: Parsing FOAF in perl?

Danny Ayers danny666 at v...
Tue Dec 10 16:22:18 UTC 2002

>In one sense there is no authoritative information - I can just as
>easily lie about myself as you. My personal belief is that each
>application has to have its own world view. It has to decide who to
>trust for itself. When it encounters contradictory statements it has
>to make some decision as to how they should be reconciled.
>That's a hard problem.

Yes. But there are non-hard ways of approaching it - from the trivial (e.g.
statements that appear at a later time get precedence) to the trickier (web
of trust reasoning). To be able to do this kind of thing it'll be necessary
to have information about the source (document) of the data. Danbri's
mentioned document-centricity, but how does that work in practice? For
example, Jena has Model classes to hold graphs, and it's easy enough to have
a Model object containing Ian's foaf statements and another to hold Jim's.
It's also easy enough to maintain provenance info, e.g. in another Model
instance, containing statements referring to the documents' URIs. But what
happens when you try and reason across these? Either you can do it
programmatically, which seems clunky, for every operation you'd have
'foreach model {doStuff}', or you could merge all the triples together into
a single model, then bigModel {doStuff}. This way you have to use the
provenance info at merge time (perhaps one-off processing, or applying it to
reified statements from the Models), but either way it seems like it needs
more work that it should in principle... I'd very much like to hear more
about how everyone's approaching this kind of situation.


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