Hi Ken, 2012-03-02 18:07 Wenzel, Ken: > Our main idea is to use OpenMath expression in the same way for reasoning as > owl:Restrictions or spin:constraints/spin:rules > (http://spinrdf.org/spin.html).
Cool! > We're currently building a prototype reasoner based on Symja > (http://code.google.com/p/symja/) > and later on Maxima (embedded with ABCL) that is able to use OpenMath > expressions > which are linked to owl:Class descriptions for computing numeric properties > of instances > (e.g. the mass of a fluid depending on its volume and density). Once more: Cool! In July we will have an OpenMath workshop in Bremen (as a part of CICM = Conference on Intelligent Computer Mathematics; see http://www.informatik.uni-bremen.de/cicm2012/cicm.php). I should really get the call for papers and an initial homepage posted soon. But a submission on your work would be most welcome. > We're currently using Manchester OWL for three reasons: > … > One of their drawbacks is, that they don't allow free variables for querying. > (But we're working on this...) > SPARQL on the other hand is much more powerful but not as well aligned > with set theory as Manchester OWL descriptions. Sounds very good to me. >> But let's talk about URIs of single resources. In the past I have >> always advocated the approach of treating them as OpenMath >> symbols, as, in fact, both are identified by URIs. > I'm also thinking that it would be possible to map RDF resource URIs to OM > symbols. > (We've also used this approach in our first prototypical implementations.) > The problem is that OM symbols should really be treated as math operators or > math constants and not as arbitrary RDF resources (classes, properties, > individuals) which > can be math symbols but they don't have to. I can understand your view and I think it is widely accepted in the OM community. But, as I said in my reply to Arnold, _I_ don't share it, for the following reasons: * It should be possible to develop mathematical models for any concept of the real world. Therefore I consider any such concept worth to be treated as a "mathematical symbol", if necessary. * RDF and OWL provide, in fact, also mathematical formalizations of the world. Just that they do it in a fixed, specific logic, whereas OM is not committed to a specific logic and easily allows for writing down higher-order constructs, if you wish. In the logics of RDF and OWL it is possible to provide mathematical formalizations of "arbitrary resources", so why shouldn't it be possible in OM? > In the end the use of strings is more aligned with the current usage of OM > symbols > and does not require an implementor to decide if an OM symbol is used as > math symbol or as reference to an RDF resource. I wouldn't speak of "deciding" – unifying the space of RDF resources and the space of OM symbols is, at least semantically, not a problem (at least not for me, see above). There is just a little technical barrier (the URI syntax). > But I am also sharing your opinion that it may be useful to introduce a > new concept like<OMIRIREF> to OpenMath. This is indeed an alternative. For this it would even suffice to introduce a symbol such as <OMS cd="www1" name="uri"/>, which would be applied to a string argument and turn it into a URI. But the result of this would be that we have an OpenMath object representing a URI, and this is no longer _so_ different from directly representing URIs via OMS. Example: <OMA><OMS cd="www1" name="uri"/><OMSTR>http://www...</OMSTR></OMA> I think this issue has been discussed before on this list, and that at least Paul Libbrecht also participated, but I don't find the mail. >> And another final question is whether (and if so, how) your CD allows >> for representing complete RDF triples as OM objects - of >> maybe this is not intended after all. > Yes, it is intended. > For example: > set1.in("This is a comment.", rdf.valueset("rdfs:comment", > rdf.resource("foaf:Person"))) > relation1.eq(rdf.value("rdfs:comment", rdf.resource("foaf:Person")), "This is > the only comment.") OK, thanks, I understand. Cheers, Christoph -- Christoph Lange, Jacobs University Bremen http://kwarc.info/clange, Skype duke4701 → SePublica Workshop @ ESWC 2012. Crete, Greece, 27/28 May 2012. Deadline 29 Feb. http://sepublica.mywikipaper.org → I-SEMANTICS 2012. Graz, Austria, 5-7 September 2012 Abstract Deadline 2 April. http://www.i-semantics.at _______________________________________________ Om mailing list [email protected] http://openmath.org/mailman/listinfo/om
