- From: Brian McBride <bwm@hplb.hpl.hp.com>
- Date: Thu, 20 Feb 2003 12:58:39 +0000
- To: "Qu Yuzhong" <yzqu@seu.edu.cn>, "pat hayes" <phayes@ai.uwf.edu>
- Cc: "rdf-comments" <www-rdf-comments@w3.org>
At 19:32 19/02/2003 +0800, Qu Yuzhong wrote: > > At 11:25 18/02/2003 -0600, pat hayes wrote: > > > > [...] > > > > >>2. About rdf:_nnn (section 3.2.2 of the RDF Semantics spec) > > >> > > >>Please consider adding one more example to clarify the meaning of > > >>rdf:_nnn, such as the following: > > >> > > >>_:xxx rdf:type rdf:Seq. > > >>_:xxx rdf:_2 <ex:a> . > > >>_:xxx rdf:_2 <ex:c> . > > >> > > >><ex:a> and <ex:c> should denote the same thing? In other words, the > > >>property rdf:_nnn should be a functional property? (I haven't found any > > >>explanation about this issue in the spec) > > > > > >Since RDFS has no notion of equality, there is no way to express the idea > > >of a functional property in RDFS. Whether or not a property is functional > > >can make no difference to any RDFS entailment. In semantic extensions > like > > >OWL which can express the idea of a functional property, it would > > >certainly be natural to impose this requirement; but then that must be > > >part of the spec of the extended language. > > > > Qu, > > > > Does Pat's explanation of the absence of this entailment resolve your > > issue, or would you like the WG to consider this as a formal last call > comment? > >Yes, RDFS has no explicit notion of equality and functional property. But >we can specify rdf:_nnn to be a functional property by an extra semantic >condition for rdf-interpretation (refer section 3.1). For example, add an >extra semantic condition as follows: > >If <x,y1> and <x,y2> are in IEXT(I(rdf:_nnn)) then y1 equals y2 in IR. > >(This also reveals the powerfulness, maybe ambitious, of the semantic >framework in the spec.) > >Pat's response partially resolves my issue. Hope the WG could consider >this as a formal last call comment. Qu, I have recorded this as a formal comment at: http://www.w3.org/2001/sw/RDFCore/20030123-issues/#qu-02 The WG will consider this and respond in due course. Thanks for your time and effort commenting on our WD's. Brian
Received on Thursday, 20 February 2003 07:57:58 UTC