[Om] Going real with the OpenMath CD Linked Data

[Christoph Lange]

Hi all,

just in time for the CICM Systems & Projects session I finished what I
had been promising for a long time: the process of publishing the
OpenMath CDs as linked data (see
http://kwarc.info/clange/pubs/krextor-system.pdf for the paper, and
http://trac.kwarc.info/krextor/wiki/OpenMathExtractionModule for a
more technical documentation as well as demos).

A short summary of what is possible now (details and demos on the
above-linked page):
* By specifying suitable MIME types in their HTTP request header,
clients can download OpenMath CDs as OCD, as RDF/XML, and as XHTML.
* The RDF description of the CDs also contains several alternative
representations of OpenMath objects: OMOBJ, Content MathML, and
Popcorn (produced using David's XSLTs)
* Mathematical properties (CMP|FMP) get semi-stable identifiers
(`cd#sym.propN`), so that they can be linked to from externally (e.g.
from the DLMF). It would however be preferable to extend the OpenMath
CD language to give them author-definable really stable identifiers
(proposal: https://trac.kwarc.info/krextor/wiki/OpenMathExtractionModule#Aproposalforreallystablepropertyidentifiers).
* One can provide RDF links and metadata about CDs without tampering
with the *.ocd files; instead it's done as standoff markup in external
RDF/XML files. I dared to commit some of them, as well as the complete
resulting RDF/XML (= RDF extracted from the *.ocd, plus additional
links/metadata), to the www/cdfiles2/cd directory. That is, there is
one thing less to worry about for, e.g. CAS: From now on I will never
ever again make disruptive suggestions such as incorporating RDFa into
the OCD language :-P

Now there is a little remaining challenge: The stuff should be
published at the canonical URIs like
http://www.openmath.org/cd/arith1#plus, so that it becomes
retrievable, but so far I have published it at a different address
just for getting the first step done.

@Paul, could I ask you for help with enabling that setup at
openmath.org?  That means:
1. I have an .htaccess file that handles the different MIME types. It
needs to be included into the Apache configuration at openmath.org.
2. The process of generating the RDF/XML files and putting them into
the right directory needs to be automated, by extending the ant build
script for the web page. As soon as (1) works, I will try that, but be
warned about stupid questions coming up.

Cheers,

Christoph

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