[Om3] Two more CDBase questions

[Christoph LANGE]

Dear James,

On Monday 12 May 2008 22:50:20 James Davenport wrote:
> > And here's now one more question about a thing that either is not
> > specified or
> > that I'm too stupid to see. For OpenMath objects we say that if a cdbase
> > is not given for a symbol, it is inherited from a parent. But what if
> > there is an
> > OpenMath object within a CD (say /CD/CDDefinition/FMP/OMOBJ) where no
> > cdbase is defined? Does that mean that the default CDBase
> > http://www.openmath.org/cd
> > applies, or does the CDBase of that content dictionary apply, i.e.
> > /CD/CDBase?
> > I think the latter would make more sense, but on the other hand it would
> > make
> > processing easier if we forced CD authors to explicitly specify the
> > cdbase for
> > every OpenMath object, if they want it to be different from the default
> > one.
>
> No - I think the former would be much easier to use. Otherwise a piece of
> OM cxan change its meaning if it is cut/pasted around. I would like to be
> able to read a definition of a symbol from a CD without having to check
> whether ordinary-looking symbols had been redefined.

Indeed, that sounds convincing; I had not thought of the copy/paste case.

But when I think about the CD editing use case, there is actually another
thing that is not clear to me. Imagine somebody is authoring a new CD
http://example.org/math/my.ocd, and most symbols in this CD "my" are defined
using symbols from the standard CDs at openmath.org. In any syntax that I can
imagine this would look quite clusmy, so I should offer some support for it in
SWiM, but I'm not yet sure what and how. Consider for example

<CD>
  <CDName>my</CDName>
  <CDBase>http://example.org/math</CDBase>
  <CDDefinition>
    <Name>foo</Name>
    <CMP>foo + 1 = bar</CMP>
    <FMP>
      <OMOBJ>
        <OMA>
	  <OMS cd="relation1" name="eq"/>
	  <OMA>
	    <OMS cd="arith1" name="plus"/>
	    <OMS cdbase="http://example.org/math" cd="my" name="foo"/>
	    <OMI>1</OMI>
	  </OMA>
	  <OMS cdbase="http://example.org/math" cd="my" name="bar"/>
        </OMA>
      </OMOBJ>
    </FMP>
  </CDDefinition>
  <CDDefinition>
    <Name>bar</Name>
    <CMP>bar - 1 = foo</CMP>
    <FMP>
      <OMOBJ cdbase="http://example.org/math">
        <OMA>
	  <OMS cdbase="http://www.openmath.org/cd" cd="relation1" name="eq"/>
	  <OMA>
	    <OMS cdbase="http://www.openmath.org/cd" cd="arith1" name="minus"/>
	    <OMS cd="my" name="bar"/>
	    <OMI>1</OMI>
	  </OMA>
	  <OMS cd="my" name="bar"/>
        </OMA>
      </OMOBJ>
    </FMP>
  </CDDefinition>
</CD>

Neither the CDDefinition of foo nor the one of bar is really easy to edit
manually, so I think that an intelligent editor could probably auto-generate
cdbase attributes if it recognizes that one of the well-known default CD names
is used, or that the name of a CD in the local knowledge base (e.g. cd="my" in
this example) is used -- as long as none of these is ambiguous.

What do you think?

Best,

Christoph

-- 
Christoph Lange, Jacobs Univ. Bremen, http://kwarc.info/clange, Skype duke4701
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