[Om] Intgraging OM with RDF [was: How to translate csymbol/@definitionURL]

Christoph LANGE ch.lange at jacobs-university.de
Mon Jul 19 16:09:06 CEST 2010

Hi Michael,

2010-07-18 13:35 Michael Kohlhase <m.kohlhase at jacobs-university.de>:
> (*) OpenMath CDs can interoperate with the Semantic Web and OM can act as a
>      "Semantics Provider for the Maths on the Semantic Web".
> I consider this as an important goal for OpenMath, and am delighted with the discussion.

thanks for stressing the "provider" role once more, that's indeed the most
important motivation for all that.

Recall that Linked Open Data is an (extremely successful) grassroots movement.
But that means that linked data publishers are quick in creating new
ontologies which [they think] suit their needs.  So if we don't demonstrate
them that we already have something well-designed that fits into their
environment, something that is much less well-designed than OpenMath might
become a de-facto standard, and once that has been "achieved", it will be much
harder to get OpenMath into use cases such as statistical datasets published
on the web.

> However, from what I see, there seem to be three (largely independent) topics concerning the OM/SemWeb integration that are discussed together that I would like to tease apart for clarity
>  1.  Extracting RDF from OpenMath CDs as a service for the Semantic Web
>  2.  Injecting objects from the Semantic Web into OpenMath
>  3.  The DLMF is possibly not Semantic-Web compliant.

If we put (3) that way, it might actually rather be discussed on some DLMF
mailing list, as the OpenMath community should only be concerned with the
subtasks of
* what things in DLMF to link to
* and using which relation(s)

>  1.  If we can extract RDF from OCDs, then we have a way to meet (*). I personally think that CLs last suggestion of adding *.rdf files to *.ocd files (just like *.sts *.ntn, ...) is closest to the OpenMath tradition here. I would suggest to open a new thread (or TRAC ticket)

I will open such a ticket soon.

> that concentrates on getting the right technically,

That's the most important question for now.

> how to author it,

RDF/XML, which is the most awkward RDF encoding that exists, will be required
for now, as it is both universally understood by RDF-based tools, and
processable by XSLT.  So I guess that for now I will be the only one
maintaining these files.

> and how to get a process going that will add this information for the CD set we have so far.

As we will now have these files separated from the *.ocd files, which are
under the control of the CD editor, I guess that I can feel free to edit them,
once a basic consensus has been found by discussing the questions of what
OpenMath CD information to link to what external datasets (e.g. FMPs to DLMF
equations), and what relations to use (but note that rdfs:seeAlso always
works).  (@James, please correct me if I'm wrong!)

> I really think that the "auxiliary file" approach is the right one for OCD here; all who like a more integrated approach can use what Christoph has developed for OMDoc CDs, there is no need to make the two approaches syntactically similar.
>  2.  If we can represent non-OM objects (e.g. math concepts from the DLMF) in OpenMath, then we can use FMPs to represent properties of these (and in particular relations to OCD-defined objects).

This contradicts the previous paragraph on "auxiliary files".  Michael, are
you suggesting (1) and (2) as two alternatives to explore?  After all the
discussion we've had, I feel up to developing a proof of concept for (1), but
I'm now skeptical about (2).

> From these we could then generate RDF to achieve (*). This solution would additionally open up the reasoning about non-OM objects in OpenMath tools and thus would put OM on an equal footing with the Semantic Web, so we should pursue it.

I have to warn you once more that the semantic web community is not interested
(or at least very hard to convince) in alternative encodings that claim to be
better than RDF.

Conversely, the OpenMath community may not be interested in dealing with
arbitrary data from the semantic web.  Consider SCIEnce, which I'd consider
the state of the art in OpenMath-based web services.  They completely ignore
the URI nature of OpenMath symbols (at least I haven't read anything about
CDBase in relation with SCIEnce), but that is not necessarily bad – they
simply don't seem to need it to achieve their goals.  But then, who would be
interested in applying "OpenMath reasoners" (e.g. CASes) to RDF data from the
semantic web?  Those reasoners that could do something useful with these data
are DL reasoners or certain rule engines, but they prefer
RDF(S)/OWL/RIF/RuleML input over OpenMath.

I used to be more enthusiastic about these things, but now I got more
realistic :-/  (And if we want to be enthusiastic about it, there is still

> There seem to be two possible solutions to this on the table.
>     *   CD-based: particular sets non-OM objects are reflected in special CDs (e.g. for the DLMF objects a "dlmf" cd).
>     *   Meta-CD-based: we develop a meta-CD that supplies a symbol that makes an OM object out of a OMSTR argument.
> The second one seems more general to me, since we can always make special-case CDs that use OM relations on OMSTR-based objects.

I'd also support the second one – something like Paul's suggestion.  Still I'm
not sure whether it would be _useful_.



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

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