- From: <herman.ter.horst@philips.com>
- Date: Wed, 26 Feb 2003 17:07:43 +0100
- To: pat hayes <phayes@ai.uwf.edu>
- Cc: www-rdf-comments@w3.org
>>RDF Semantics document, >>last call version, 23 january 2003 >>These comments were mailed earlier to the WebOnt WG [1]. > >This response extends and corrects my earlier reply. > >>A consequence of the (new) setup of the RDF semantics >>is that for each occurrence of IEXT(x) or ICEXT(x), it >>should be clear that x is in the domain of the function >>involved. (For IEXT, this domain is the set IP. >>For ICEXT, the domain is the set IC; compare my >>other comment on this to rdf-comments [2].) >>For example, in Section 3.3 the semantic conditions on >>subClassOf and subPropertyOf take care of this explicitly. >>It seems that this point is not taken care of completely >>consistently throughout the document. > >After checking the various cases, I believe that the semantic >conditions as stated completely define all the relevant domains and >ranges. > >> >>In Section 3.1, RDF interpretations, >>in the table defining an rdf-interpretation, IEXT(I(rdf:type)) >>is used before it is clear that I(rdf:type) is in the >>domain of this function (i.e., the set IP). >>Switching the first two lines of this table would remedy this. > >Done. > >> >>Similarly, it seems appropriate to move the semantic >>conditions on IC and IP in Section 3.3: >>> IC contains ...[many items] >>> IP contains ...[many items] >>to become the first conditions, as each of the other >>conditions in this table actually uses one or more of these >>conditions. > >Done. For the record, I do not regard the order of these items as >significant or meaningful. > >> >>The semantic conditions on rdfs:range and rdfs:domain in Section 3.3 >>do not yet incorporate explicit domain assumptions as just >>discussed. It seems that additions such as the following need >>therefore to be made: > >The additions suggested are not required, since they follow from the >axiomatic triples in the next table and the other conditions on range >and domain. > >It is probably easiest to express the reasoning in terms of triples >that must be satisfied by an interpretation I. For example, suppose ><x,y> is in IEXT(I(rdfs:range)), ie that > >I |= (x) rdfs:range (y) I do not understand this step. In these two lines x/y have a different origin. In "<x,y> is in IEXT(I(rdfs:range))", x and y are in IR. In the triple "(x) rdfs:range (y)", x and y are uri's or blank nodes (y may also be a literal). So this conclusion ("ie that") is not clear. >Now, since >I |= rdfs:range rdfs:domain rdf:Property . (axiomatic triple) > it follows by the semantic condition on rdfs:domain that >I |= x rdf:type rdf:Property . >ie, by the basic condition on IP, that x is in IP. > >Similar reasoning using a different axiomatic triple shows that y >must be in IC. > > >Pat > >> >>If <x,y> is in IEXT(I(rdfs:range)) >>[then x is in IP and y is in IC] and >>[if, in addition,] <u,v> is in IEXT(x) then >>v is in ICEXT(y) >> >>If <x,y> is in IEXT(I(rdfs:domain)) >>[then x is in IP and y is in IC] and >>[if, in addition,] <u,v> is in IEXT(x) then >>u is in ICEXT(y) >> >>The last call versions of these statements (i.e., this text >>without the [...]-additions) seem to be >>remnants from the April 2002 version of the RDF MT, where >>IEXT as well as ICEXT had all of IR as their domain. >> >>Herman ter Horst >>Philips Research >> >>[1] http://lists.w3.org/Archives/Public/www-webont-wg/2003Feb/0067.html >>[2] http://lists.w3.org/Archives/Public/www-rdf-comments/2003JanMar/0348.html > > >-- >--------------------------------------------------------------------- >IHMC (850)434 8903 or (650)494 3973 home >40 South Alcaniz St. (850)202 4416 office >Pensacola (850)202 4440 fax >FL 32501 (850)291 0667 cell >phayes@ai.uwf.edu http://www.coginst.uwf.edu/~phayes >s.pam@ai.uwf.edu for spam > >
Received on Wednesday, 26 February 2003 11:09:45 UTC