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XML Schema for OWL

From: Raphael Volz <rvo@aifb.uni-karlsruhe.de>
Date: Wed, 19 Jun 2002 17:08:19 +0200
To: "Peter Patel-Schneider" <pfps@research.bell-labs.com>
Cc: "Webont" <www-webont-wg@w3.org>
Message-ID: <DMECLAFLIOFJEFFIAJPCIENCCMAA.rvo@aifb.uni-karlsruhe.de>
Hi Peter -

I finally had time to have a look to your XML Schema.

First, I assume that all non-logical things like rdf:labels
etc are left out for this first version and will be included at some later

Regarding the definition of OntologyType:
Why do you use the plural for the elements "EquivalentClasses",
"DisjointClasses","EquivalentProperties","DifferentIndividuals" ?
With respect ot "EquivalentClasses" I do not understand how your example can
validate against the schema. In the example you use the singular form
"EquivalentClass"  to declare "Student".

Is the ability to specify SubClassOf and SubPropertyOf separately from the
Class and Property definition directly
under the ontology definition intended ?

Regarding ClassAxiom:
I can't understand the last attribute in the definition of class axioms:

 <xsd:complexType name="ClassAxiom">    <!-- RDF description ...
  <xsd:attribute complete="complete" type="xsd:boolean" use="required" />

There is no attribute "complete" in XML Schema for xsd:attribute ( see
http://www.w3.org/TR/2001/REC-xmlschema-1-20010502/#element-attribute )

Regarding the definition of "SubClassOfType":
You can omit the minoccurs and maxoccurs for sub and super elements since
they take the default values anyways.

The same holds for SubPropertyOfType.
The same holds for DataType / OnfeOf in DataRange.
The same holds for Class etc. in DescriptionType.
The same holds for SingleDescription.
The same holds for RestrictionType.

Within DataRestrictionType and IndividualRestrictionType:
is the ability to specify arbitrary numbers of allValuesFrom and
someValueFrom (at the same time) really intended ? To me this does not make
sense and should be appropriately restricted.

General Remarks:
I'ld suggest that a general pattern for the definition
of multiple occurences is used.

Sometimes you establish cardinalities with the sequence
(for example at the definition of OntologyType) and sometimes
with the element itself (for example at the definition of Enumeration).

Also I'ld suggest to have a general pattern for naming, which
is partially there, e.g.:

Ontology -> OntologyType
Include -> IncludeType
SubClassOf -> SubClassOfType

on the other hand you use:
Class -> ClassAxiom
EnumeratedClass -> Enumeration

Third the requirement of having the readability of the
XML through RDF leads to quite many spare nestings which
will lead to even more anonymous triples in the very end.

Best regards,


PS: I'll try to come up with an alternative concerning
the last problem but this may take a while to get done.

 Raphael Volz             Tel:   49 721 608-7363
 Institut AIFB            Web:   http://www.aifb.uni-karlsruhe.de/WBS/rvo
 Uni Karlsruhe (TH)       EMail: volz@aifb.uni-karlsruhe.de
 PGP-Key Fingerprint:
	C5A1 52FA D0F1 47B9 7075  1F22 F3E3 BEE2 68BB 1643

Received on Wednesday, 19 June 2002 11:09:23 UTC

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