Question on csymbol usage

[Andreas Maier-4]

Hi,
I am relatively new to MathML and I am exploring its use for describing
logic expressions of certain boolean conditions that we define in our
domain. The resulting MathML expression would be embedded in an XML
instance document that describes our domain in certain terms, and when that
description needs to express a logic expression of our boolean conditions,
it would use a MathML fragment.

There are about a handful of these boolean conditions. An example would be
"the feature f has been implemented". The idea is to represent that boolean
condition as a user defined MathML operator (e.g. named "featureimpl") over
the feature name (e.g. "name").

So for the logic expression:

   "feature f1 has been implemented or feature f2 has been implemented"

the MathML expression would have the structure:

   or( featureimpl (f1), featureimpl (f2) )

I understand that the csymbol operator can be used to define user defined
operators, e.g.:

   <apply>
       <csymbol encoding="text"
   definitionURL="http://some.org/featureimpl">featureimpl</csymbol>
       <ci>name</ci>
   </apply>

What is not clear to me is how I would place a MathML fragment containing
the *definition* of such an operator into a common XML instance document,
separate from the MathML fragment *using* the operator in another XML
instance document (that would include the common XML instance document).

Does the MathML fragment shown above represent the definition of the
operator, or its usage (in which case, the content of the <ci> element
would need to be changed to the actual feature names, e.g. f1 or f2) ?

Andy

Andreas Maier
IBM Senior Technical Staff Member, Systems Management Architecture & Design
IBM Research & Development Laboratory Boeblingen, Germany
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[ChristophLange]

Hi Andreas,

2009-10-12 08:41 Andreas Maier <MAIERA@...>:
> What is not clear to me is how I would place a MathML fragment containing
> the *definition* of such an operator into a common XML instance document,
> separate from the MathML fragment *using* the operator in another XML
> instance document (that would include the common XML instance document).
>
> Does the MathML fragment shown above represent the definition of the
> operator, or its usage (in which case, the content of the <ci> element
> would need to be changed to the actual feature names, e.g. f1 or f2) ?

Your fragment _uses_ the operator, but does not define it.  With MathML alone,
there is no way of defining operators.  MathML can _use_ so-called content
dictionaries (see http://www.w3.org/TR/MathML3/chapter4.html#contm.cds),
which contain definitions of operators, but it cannot be used to write them.
XML languages for writing content dictionaries are, e.g., OpenMath
(http://www.openmath.org) or OMDoc (http://omdoc.org).

Hope that helps,

Christoph

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