W3C home > Mailing lists > Public > www-rdf-logic@w3.org > February 2001

RE: universal languages

From: pat hayes <phayes@ai.uwf.edu>
Date: Mon, 5 Feb 2001 23:05:19 -0600
Message-Id: <v04210122b6a53390a1f8@[205.160.76.246]>
To: Peter Crowther <Peter.Crowther@melandra.com>
Cc: www-rdf-logic@w3.org
> > From: Dan Connolly [mailto:connolly@w3.org]
> > Sent: 02 February 2001 23:18
>[...]
> > Triples are an idiom that show up all over the place,
> > in my experience. They look like a pretty important
> > and useful modelling primitive.
>
>You can model a directed graph using a set of triples; you can model an
>arbitrarily complex data structure with a directed graph.  As primitives,
>they are sufficient to model any other structure.

That depends on what you mean by 'model' (and 'structure'). They are 
sufficient to *implement* any finite directed graph, indeed, in 
common with a host of alternative datastructuring primitives (eg LISP 
s-expressions based on dotted pairs). They are not so suitable for 
efficiently representing numerically indexed structures such as 
arrays and tables, and they are only suitable for representing 
linguistic structures such as structured code or logical expressions 
if supplemented with some conventions for binding label names and 
indicating scope boundaries. (All of this is well-known, almost 
classical, in both the logic and programming communities and has been 
for about 40 years or more: I learned it at grad school and it was 
considered ancient lore way back then.)

Triplet structures have their uses, but the almost irrational passion 
revealed for them by members of the RDF community remind me of what 
happened when I once questioned Christian doctrine on a 
fundamentalist email list.

Pat Hayes

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Received on Tuesday, 6 February 2001 00:02:37 GMT

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