Dear James, 2010-01-27 09:43 Professor James Davenport <[email protected]>: > I found this a useful reminder that we really ought to address the "RDF > and OpenMath" issue.
I'm up to that; I have always been interested in exploring that connection. In my soon-to-be-finished thesis there will be a lot of elaboration on that. And, BTW, the way how I learnt about SCOVO is that a friend working on semantic web topics contacted me and asked me how they should reasonably express the mathematical relations between individual data points in RDF. E.g. if http://statistics.db/Germany#GDP2009 is described as having the numeric value V1, the unit €, some origin, further metadata, etc., if http://statistics.db/Germany#GDP2010 is described as having the numeric value V2, and if there is another data point http://statistics.db/Germany#GDPGrowth20092010 with numeric value V3 and "unit" percentage points, that the mathematical relation is V3 = V2/V1 * 100 - 100. Well, I said that it's certainly straightforward to write it down in Content MathML or OpenMath, using e.g. <csymbol definitionURL="http://statistics.db/Germany#GDP2009"/> or <OMS cdbase="http://statistics.db"; cd="Germany" name="GDP2009"/> for the data points (the latter works here, but is problematic in general, as not all URIs from the RDF works have the form aaa / bbb # ccc). It is less straightforward and maybe neither desirable nor reasonable to translate that to a pure RDF representation. Massimo Marchiori suggested such a translation at MKM 2003, but to the best of my knowledge that never really been adopted. RDF usually only supports binary predicates, plus certain cumbersome data structures that reasoners rarely support, but for adequately representing n-ary operators one would have to use those list- or array-like data structures. So in the end I suggested looking at one of the existing RDF-based unit ontologies; it might be the case that some of them have semiformal definitions of binary arithmetic operators allowing you to say (in RDF) e.g. S rdf:type :Sum. S :result X. S :firstArg Y. S :secondArg Z. Maybe that is actually the best way to go; and maybe it would be enough for us if the definition of that "Sum" "operator" were somehow linked to http://www.openmath.org/cd/arith1#plus. Cheers, Christoph -- Christoph Lange, Jacobs Univ. Bremen, http://kwarc.info/clange, Skype duke4701
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