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xml:base as context/space URI? was Re: summary of 'a triple is not unique' and 'statements/reified' statements

From: Jonathan Borden <jborden@mediaone.net>
Date: Tue, 28 Nov 2000 17:34:04 -0500
Message-ID: <017001c0598b$51a66740$0a2e249b@nemc.org>
To: "Sergey Melnik" <melnik@db.stanford.edu>, "Seth Russell" <seth@robustai.net>
Cc: "RDF Interest Group" <www-rdf-interest@w3.org>, "Libby Miller" <Libby.Miller@bristol.ac.uk>
Sergey Melnik wrote:


> Seth Russell wrote:
> > ...
> > In defense of Sergey's proposal, I would like to withdraw my allegation
that
> > it would necessarily be less efficient for expressing context
information.
> > As the examples below show, either method could be equally as efficient.
> >
> > My method:
> > [id7, context1, asserts, t1]
> >
> > Sergey's method:
> > [id8,t1, istin, context1]
...
>
> So, the two different representations above are nothing but developer's
> choice. In fact, our in-house database implementation uses what you call
> "My method" above, if you replace "asserts" by "contains"...
>

    How about:

<rdfs:Class ID="Context">
    <rdfs:subClassOf rdf:resource="rdf:Bag" />
</rdfs:Class>

or

<rdfs:Class ID="Space">
    <rdfs:subClassOf rdf:resource="rdf:Bag" />
</rdfs:Class>


Now we are getting to the point where we can define the term "context" or
"space" as a bag of statement references. The problem I see is with rdf:Bags
which are define membership by the arcs _1,_2 ... -- this naming convention
is fine for sequences but implies an ordering on members of Bags which are
unordered. The reason this is a problem is for creating a context with
statements from multiple documents and perhaps from multiple
rdf:Description's ... the implementation needs to keep track of statement
ordering (for example suppose I want to extend my rdfExtractify to spit out
statement triples which denote context membership ...).

One might also argue that <rdf:Description bagid="..."> limits the context
URI as prefixed by the current document *but* suppose:

<rdf:Description xml:base="SpaceURI" bagid="">
    <a:foo ID="S1">...</a:foo>
    <a:bar ID="S2">...</a:bar>
</rdf:Description>

wouldn't this provide for assigning statements to a desired context/space (I
am using the term "space" so as not to 'step on' other uses of the term
context ... but in my usage the two are synonymous).

Suppose we agree, I would then prefer to write:

[spaceURI, contains, S1]
[spaceURI, contains, S2]

rather than:

[spaceURI, _1, S1]
[spaceURI, _2, S2]

Jonathan Borden
The Open Healthcare Group
http://www.openhealth.org
Received on Tuesday, 28 November 2000 17:46:22 GMT

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