[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: XML-based Automation (Was: Zen or Games?)
[Danny Ayers] > > > > [Danny Ayers] > > > ... > > > CGs and RDF have a lot in common. Taking the main points of the abstract > > > syntax for CGs in the ISO standard [1] it's possible to map > > across fairly > > > directly to aspects of RDF (this is a 2 minute, first shot attempt) : > > > > > > 6.3 Conceptual Relation - Statement (/Property) > > > > Disagree. "In a conceptual graph, the boxes are called concepts, and the > > circles are called conceptual relations." (Sowa 2000, p476). RDF has no > > conceptual relations. They have to be simulated, most likely with bnodes. > > Hmm, I would have thought that most of the time CG conceptual relations > would have mapped directly to RDF properties : > In general, CG conceptual relations are n-ary, not binary. Simulating an relation with valence of 5, say, by using a bnode could be done, but there is no way, even with OWL, so far as I can see, to declare a restriction on the number and types of predicates that the bnode must have to match the valence of the CG relation. > From the CG tutorial [1] : > > A cat is on a mat. > > CG version (approx) : > > [Cat]->-(On)->-[Mat] > From CG examples at http://users.bestweb.net/~sowa/cg/cgexamp.htm#Ex_4 "A person is between a rock and a hard place}" - a relation of arity 3 [Person]<-(Betw)- <-1-[Rock] <-2-[Place]->(Attr)->[Hard].You need to convert the (Betw) relation to a bnode to simulate this. > > > 6.7 Referent - Object (of statement) > > > > Disagree. A referent is essential an identifier (Sowa, p 424). > > Ok, I must have misinterpreted that - URIref instead then. > Nope, a referent can have a complex structure (includng wildcards and variable names). I suspect that a compex referent would be impractical to represent by a URI. > Yep, RDF itself is essentialy just e-c. But it's possible through the use of > RDFS to create terms outside the core, and then give those terms more than > what's found in base level RDF. e.g. let's have : > > xmldev:not rdfs:subClassOf rdf:Property > > and with a bit of verbal fluff we have negation. > Wrong model - not() is a monadic relation, not binary. RDF can have no monadic relations, even with [name your favorite] layered on top. In RDF it is painful at best to refer to some particular GC-like context (an arbitrary subgraph), because subgraphs are not identifiable. You have to invent something equivalent to rdf:Statement, but more general. Unpleasant. Anyway, the degree of extension to RDF needed would be significant. You need negation and quantification, at least. Cheers, Tom P
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