Re: How to use CDBase URIs in Content MathML?

David Carlisle wrote:
> On 12/07/2010 14:30, Christoph LANGE wrote:
> > OK, but I'm still confused:  How would I translate the following to
> > Content MathML?
> > 
> > <OMOBJ>
> > 
> >    <OMA>
> >    
> >      <OMS cdbase="http://example.org/cd" cd="foo" name="bar"/>
> >      <OMS cdbase="http://somewhere.com/cd" cd="foo" name="baz"/>
> >      <OMS cdbase="http://frobnitz.org/cd" cd="foo" name="fnord"/>
> >    
> >    </OMA>
> > 
> > </OMOBJ>
> > 
> > I.e. what do I do when one formula uses symbols from CDs that have
> > the same relative name but under different CDBase URIs?
> > 
> > And why is there no csymbol/@cdbase?
> 
> We went through 1001 permutations of specifying how cdbase and
> inherited attributes and compatibility with mathml2 markup were
> supposed to work and in the end came to the version in the current
> draft (earlier drafts before the 1st last call had different
> variants as I recall)
> 
> cdgroup files dont currently allow aliasing[although see below] so
> currently you would need to set up the alias externally, that is you
> could have the mathml
> 
> <math cdbase="http://example.com/mycdgroup.xml">
>    <apply>
>      <csymbol cd="foo1">bar</csymbol>
>      <csymbol cd="foo2">baz</csymbol>
>      <csymbol cd="foo3">fnord</csymbol>
>    </apply>
> </math>
>
> with the mycdgroup.xml group file referring to renamed copies of the
> original cd files (either actual copies or some kind of server
> redirect set up at example.com.

You mean cdgroup="http://example.com/mycdgroup.xml", right?
IMHO using a cdgroup file for this is dangerous. It could become 
necessary to generate them based on the situation at hand, but if two 
pieces of software communicate, there is perhaps no way to hand over a 
dynamically generated cdgroup file.

> the cdbase property is an optional openmath property in openmath2 and
> not there at all in openmath 1, 

But it _is_ a property in openmath2, right?

> and while it's useful as a location
> aid to find cd files I've never seen it used in practice to
> disambiguate cd files of the same name. The OpenMath CD review
> system has always assumed so far that any public CDs have unique
> names (hence the numbered names arith1, arith2 etc to allow easily
> naming variants)
> 
> so while the need to rename the files is a theoretical wart hopefully
> it isn't an issue in practice. Even in the OM syntax, if there is a
> real possibility of those three cds being used together, then giving
> them different names would probably be a good idea.

Isn't this the same as claiming that there is no need for a namespace 
mechanism for XML because elements would have unique names anyway?

And please remember that the content dictionaries published by OpenMath 
are not the only ones! There are already content dictionaries in use 
that are not even published in any way.

Greetings
Urs

Received on Monday, 12 July 2010 14:56:55 UTC