[Crm-sig] *** ISSUE *** Revision of scope note for E73 Information Object to specifically include named graphs

Simon Spero sesuncedu at gmail.com
Thu Jul 24 22:58:23 EEST 2014


On Thu, Jul 24, 2014 at 4:03 AM, Richard Light <richard at light.demon.co.uk>
wrote:

>
> I must say that I'm not so sure that named graphs are going to be
> particularly useful for implementations of the CRM.  As I understand it
> (and I don't claim to be an RDF expert), the idea of quads was invented so
> that "naked" RDF assertions could be given a "context".  The problem I have
> always had with that idea is that you only get one shot at it (i.e. you can
> only assign one context to any given triple).
>

A triple is a true proposition*; duplicates are redundant (A and A <-> A).
 However, there can be multiple speech acts asserting that the  proposition
is true.  There are ways of giving semantics to named graphs that enable
that; however, the semantics of named graphs were deliberately left
underspecified (a decision that was not uncontroversial).

In the end, what was published was a Working Group Note listing some of the
possibilities that were argued for - see:
http://www.w3.org/TR/rdf11-datasets/ .

There are other possible semantics that named graphs might have ; for
example, the name in a named graph might denote some graph containing the
reified forms of the statements in the graph part of the named graph. This
differs from the quotational semantics given in §3.7 of the note cited
above given the presence of  blank nodes - ("one does not simply quantify
into quoted contexts!").

Since the CRM does not require that the propositional content of an
propositional object be true, it might be possible to avoid these questions
by dealing with  Graphs (as sets of propositions), and assertions of the
contents of those Graphs directly .

Simon

* which is why, now that RDF 1.1 make any triple will an ill-typed literal
false, any graph that contains such  triple is inconsistent.
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