Proposal to resolve two XSD datatype issues

PROPOSAL: Close ISSUE-87 without further action

PROPOSAL: Resolve ISSUE-88 by adding xsd:duration to the list of supported XSD datatypes in RDF 1.1

Details/justifications below.


== ISSUE-87 ==

Some RDF datatypes included in RDF 2004, such as xsd:gYear, have proven troublesome in RIF and OWL due to not being well-behaved w.r.t. ordering. Revisit them to decide if anything is to be done about it.

Ivan said:
> I do not see why we would have to do that. These datatypes are obviously useful in RDF and, actually, are used (eg, the microdata->RDF specification recommends using those). OWL and RIF has good reasons not to use them, but that is not binding for RDF imho.

Hence the proposal.

== ISSUE-88 ==

RDF 2004 says that xsd:duration does not have a well-defined value space. The value space of xsd:duration has been re-defined in XML Schema 1.1, so this needs to be revisited.

Alex Hall reviewed this (Thanks Alex!) and said:

The duration definition in XSD 1.1 does have a clearly defined:
    lexical space, which is the same as that in 1.0
    value space, which is modeled as a [ months as xsd:integer, seconds
     as xsd:decimal ] tuple.
    identity condition: two durations are identical if and only if their
     months and seconds components are both identical.
    equality relation, which is the same as its identity relation.
    partial ordering.

Given these revisions, we should consider including xsd:duration in the
list of RDF-compatible XSD types.

Peter went and asked the OWL, RIF and SPARQL WGs to check for objections (Thanks Peter!):

This generated quite some chatter, but the only substantive technical comments on the issue came from Michael Schneider, who summarised his position here:

As our intention is to only add xsd:duration to the XSD datatype map (which is optional), Michael's view can be summarized as:

Why should we (the OWL WG) care about xsd:duration? It'll be just yet another datatype that is in RDF but not in OWL 2 and RIF.

Which is a view that was also expressed by Pat and others in one of our recent calls.

Hence the proposal.

The required document change is simply to do the obvious thing in this section of RDF Concepts ED:

Received on Wednesday, 9 May 2012 23:43:05 UTC