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Update to The MathML3 DTD

From: David Carlisle <davidc@nag.co.uk>
Date: Mon, 03 Feb 2014 14:11:07 +0000
Message-ID: <52EFA37B.7020708@nag.co.uk>
To: "'www-math@w3.org'" <www-math@w3.org>

The MathML3 DTD has been updated at


There are no changes to the set of documents that are valid, just to the
structure of the internal parameter entities.

MathML2 declared the id and xref attributes as type ID and IDREF

This is natural when considering a MathML expression in isolation but
means that separate MathML expressions when incorporated into larger
document have to have globally unique IDs, which is not always easy to

Partly as a result of this concern, and partly as an artefact of the
translation from Relax NG, the MathML3 DTD declares these attributes as
CDATA so does not enforce the unique id requirement.

In general this is fine but it can cause problems for people updating
from MathML2 using toolchains requiring ID processing, so we have added
parameter entities to allow the type to be switched.

The declarations of the attributes are now


where %IDTYPE; defaults to CDATA, but if you wish to import the MathML3
DTD having id declared as ID then just include the declaration


before including the MathML DTD.

A similar problem incorporating the MathML3 DTD into larger document
types was the use of the parameter entities such as product.class
used (mostly in the Content MathML declarations). The .class convention
is fairly common and this has lead to name clashes, as the names must be
unique when DTDs are combined. We've renamed all such parameters to
.mmlclass so product.mmlclass. These entity names are not intended for
external use, just for internal structuring if the DTD, so this change
should not affect any documents.


At least until the page is updated, you can see problems caused by the
previous version of the DTD in a real example at


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Received on Monday, 3 February 2014 14:11:40 UTC

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