- From: Paul Gearon <pag@tucanatech.com>
- Date: Sat, 9 Oct 2004 17:21:39 +1000
- To: www-rdf-interest@w3.org
On 09/10/2004, at 4:32 PM, Paul Gearon wrote: > On 07/10/2004, at 7:50 AM, Charles McCathieNevile wrote: >> On Wed, 6 Oct 2004, Jan Algermissen wrote: >>> Since the graph is a set it does not contain duplicate triples, yes? >> >> I recall a discussion on this topic recently. I believe that someone >> who >> knows the spec better than I do said the formal definition doesn't >> prohibit >> redundant triples, so a conformant program would not necessarily >> delete >> them... > > I can't comment on the formal spec on this specific point, as I > haven't checked it [1] OK, I've looked now. The RDF Semantics document says: "An RDF graph, or simply a graph, is a set of RDF triples." This document uses the words "set" and "subset" in a formal sense. The phrase "RDF graph" is linked to the RDF Concepts and Abstract Syntax document, which uses semi-formal set algebra to describe its definitions. So when they say "set", they really do seem to mean it. Hence, no duplicates. However, it should be noted that the RDF/XML Syntax spec says: "Software transforming RDF/XML into a representation of a graph MAY eliminate duplicate predicate arcs." This statement also says that as far as RDF/XML is concerned, duplicate statements are not considered significant. But if you require that statements are unique in a graph then you need to check the system you are using. Regards, Paul Gearon Software Engineer Tucana Technologies http://www.tucanatech.com Catapultam habeo. Nisi pecuniam omnem mihi dabis, ad caput tuum saxum immane mittam. (Translation from latin: "I have a catapult. Give me all the money, or I will fling an enormous rock at your head.")
Received on Saturday, 9 October 2004 07:22:19 UTC