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DRAFT RDF Core review of Requirements for XML Schema 1.1 WD 2003-01-21

From: Dave Beckett <dave.beckett@bristol.ac.uk>
Date: Fri, 14 Mar 2003 10:24:56 +0000
To: w3c-rdfcore-wg@w3.org
Message-ID: <18293.1047637496@hoth.ilrt.bris.ac.uk>


My apologies for the delay on this.

Many words taken from Jeremy's mail:
  http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003Jan/0163.html

but this was meant to be a skeleton for XSD experts such as Jeremy
and and Patrick to fill in/argue about ;)

Dave


DRAFT review of 
  Requirements for XML Schema 1.1
  W3C Working Draft 21 January 2003
  http://www.w3.org/TR/2003/WD-xmlschema-11-req-20030121/
  for RDF Core WG 

RDF Core's primary concerns on XML schema datatypes is that the
maximum number of constructs are named by URI references and that the
identity and equality relations are clearly defined.


1. First class objects (RQ-23)
  http://www.w3.org/TR/2003/WD-xmlschema-11-req-20030121/#N400183

The lack of URIrefs for user defined simple datatypes presents a
substantial difficulty for the use of XML Schema datatypes in RDF and
OWL.

We strongly ask that:
   Either RQ-23 be raised to a requirement, or a new requirement of
   URIs for simple types is added.

Not speaking for the  WebOnt WG, but we note additionally that it has
postponed an issue on incorporating XML Schema complexTypes within OWL:
  http://www.w3.org/2001/sw/WebOnt/webont-issues.html#I4.3-Structured-Datatypes
which would also benefit greatly from unique URI references for each
user defined XML Schema datatype.  The reason for postponing was
given as:
  [[ XML Schema WG hasn't yet decided how XML schema
     components fit into URI space.]]
  -- http://lists.w3.org/Archives/Public/www-webont-wg/2002Oct/0157.html
so would probably also support this requirement being strengthened.


2. Systematic treatment of fundamental facets (RQ-24)
  http://www.w3.org/TR/2003/WD-xmlschema-11-req-20030121/#N40024F

Equality is a fundamental issue in the use of XML Schema datatypes in
the semantic web, particularly OWL, and to a lesser extent RDF.  

We ask that you would:

  Define the equality relation clearly.

  Define the identity relation clearly.

    In particular we understand from XML Schema 1.0 that this is the
    same as the mathematical relation of quantitative equality.  The
    RQ24 wording tends to suggest that there is a difference.

We refer you to Jeremy Carroll's study of equality of XML Schema datatypes
  http://lists.w3.org/Archives/Public/www-archive/2002Nov/att-0092/02-index
for further analysis and information.



3. Add URI datatype (RQ-108)

We moderately supporting this since URIs are used distinguished from URIrefs.
Such as in xml:base attribute values?
Received on Friday, 14 March 2003 05:27:36 EST

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