- From: Michael Hucka <mhucka@caltech.edu>
- Date: Fri, 22 Apr 2005 19:39:02 -0700
- To: www-math@w3.org
There are two oddities about the definitino of 'cn' in the MathML schema that I'm hoping other people can help me understand. I'm referring here to the schema available at http://www.w3.org/Math/XMLSchema/. 1. The definition of 'cn' allows empty content. In content/tokens.xsd, there is the following: <xs:complexType name="cn.type" mixed="true"> <xs:group ref="cn.content" minOccurs="0" maxOccurs="unbounded"/> <xs:attributeGroup ref="cn.attlist"/> </xs:complexType> <xs:element name="cn" type="cn.type"/> However, it is not clear to me what meaning this would have. It is also not clear to me that the MathML spec itself allows empty content in 'cn' elements. (Does it?) 2. The definition of 'cn' content is the following: <xs:group name="cn.content"> <xs:choice> <xs:group ref="Presentation-expr.class"/> <xs:element ref="sep"/> </xs:choice> </xs:group> Looking up 'Presentation-expr.class', we find that it is defined in common/math.xsd as (perplexingly): <xs:group name="Presentation-expr.class"> <xs:choice> <xs:group ref="PresExpr.class"/> <xs:group ref="ContExpr.class"/> </xs:choice> </xs:group> This appears to me to allow unrestricted MathML content to be present as the content of a 'cn' element. However, according to section 4.4.1.1.1 of the MathML-20031021 spec, it seems that the only content that should be allowed are character sequences possibly separated by <sep/>. Are my interpretations of MathML and/or the XML Schema incorrect? I'd appreciate any feedback. MH -- Mike Hucka, Ph.D. Senior Research Fellow mhucka@caltech.edu Control and Dynamical Systems 107-81 tel: +1.626.395.6911 Caltech, Pasadena, CA 91125, USA fax: +1.702.554.3067
Received on Saturday, 23 April 2005 02:39:11 UTC