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[Semantic Web]为什么rdf:predicate 的 range 为 rdfs:Resource,而不是rdf:Property 读书笔记,  科学研究 {{ // RDF Schema Recommendation( http://www.w3.org/TR/2004/REC-rdf-schema-20040210/#ch_predicate ) 5.3.3 rdf:predicate rdf:predicate is an instance of rdf:Property that is used to state the predicate of a statement. A triple of the form: S rdf:predicate P states that S is an instance of rdf:Statement, that P is an instance of rdf:Property and that the predicate of S is P. The rdfs:domain of rdf:predicate is rdf:Statement and the rdfs:range is rdfs:Resource. }} 为了使得reification可以表达不合法的RDF陈述。 I also dimly recall this decision being made, and that at the time the reasons seemed good to me. I don't think it was because the narrower interpretation presented any particular mathematical difficulties. It may have been the observation that reification should be able to describe 'illegal' RDF, in which a non-property URIreference is used in a predicate position in a triple. At any rate, the mere possibility of such an error occurring means that one should not be able to conclude, merely from the fact of a URI being used in some RDF in this position, that it really does, in fact, denote a genuine property (which would be the effect of having the range be rdf:Property) It might be worth remarking that to have rdfs:Resouce as a domain or range is never an error, since in RDFS domains and ranges can be conjoined. It is more like a kind of resignation: one is saying that the subject or object of the property may be anything whatsoever, unless of course further information is supplied which restricts them in some other way or for some other reason. One can see this by looking at the RDFS inference rules (http://www.w3.org/TR/2004/REC-rdf-mt-20040210/#RDFSRules), whererdfs3 allows you to conclude in this case that the type of the object of any assertion of rdf:Property must be rdfs:Resource; but one knew that already, from rdfs4b. So this 'vacuous' range only provides some redundant information. Pat Hayes     The problem had to do with OWL compatibility.  See http://lists.w3.org/Archives/Public/www-webont-wg/2003Oct/0188.htmland the minutes athttp://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003Nov/0063.html(I was curious, and looked a few things up). --Frank     徐涵（Han Xu） 发表于 2004/12/12 16:31:03 | 阅读全文(2283) | 回复(0) | 编辑 | 精华

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