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Re: question about lexical and value spaces

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Wed, 09 Jan 2008 11:41:54 -0500 (EST)
Message-Id: <20080109.114154.266086409.pfps@research.bell-labs.com>
To: mike@saxonica.com
Cc: www-xml-schema-comments@w3.org

Hmm.  I hadn't thought of that issue.

The kind of datatype that I was interested in was a datatype with
uncountably many values, e.g., reals.  In XML Schema 1.0 one could not
have such a datatype, but it appears to my reading that they would be
allowed in XML Schema 1.1, and I was checking whether this was actually
the case.

The OWL WG is interested in this as there is a proposal to add a real
datatype to OWL 1.1.

Peter F. Patel-Schneider
Bell Labs Research



From: "Michael Kay" <mike@saxonica.com>
Subject: RE: question about lexical and value spaces
Date: Wed, 9 Jan 2008 16:50:21 -0000

> There is intense debate about whether "ineffable values" (values with no
> lexical representation) should be considered as being within the value space
> or not. An example of such a value is a list of three zero-length strings.
> In some sense the point is metaphysical, since it doesn't affect the
> legality of schemas or the validity of instance documents. But it's a hot
> topic within the Working Group all the same. Watch this space.
> 
> Michael Kay
> http://www.saxonica.com/
> 
> > -----Original Message-----
> > From: www-xml-schema-comments-request@w3.org 
> > [mailto:www-xml-schema-comments-request@w3.org] On Behalf Of 
> > Peter F. Patel-Schneider
> > Sent: 09 January 2008 14:11
> > To: www-xml-schema-comments@w3.org
> > Subject: question about lexical and value spaces
> > 
> > 
> > I have a question about the relationship between lexical and 
> > value spaces in XML Schema datatypes.
> > 
> > In XML Schema 1.0 each value has to have at least on lexical 
> > representation, as evidenced in 
> > http://www.w3.org/TR/2004/REC-xmlschema-2-20041028/#value-space
> > 
> > *********************
> > 2.2 Value space
> > 
> > [Definition:]  A value space is the set of values for a given 
> > datatype. Each value in the value space of a datatype is 
> > denoted by one or more literals in its lexical space. 
> > *********************
> > 
> > However I cannot find this requirement in XML Schema 1.1.
> > 
> > Is it true that this is a change between XML Schema 1.0 and XML Schema
> > 1.1?   (By the way, I am completely in favour of this change.)
> > 
> > Peter F. Patel-Schneider
> > Bell Labs Research
> > 
> 
Received on Wednesday, 9 January 2008 17:07:51 GMT

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