- From: Brian McBride <bwm@hplb.hpl.hp.com>
- Date: Tue, 25 Feb 2003 14:38:19 +0000
- To: pat hayes <phayes@ai.uwf.edu>, herman.ter.horst@philips.com
- Cc: www-rdf-comments@w3.org
At 14:23 24/02/2003 -0600, pat hayes wrote: >>RDF Semantics document, >>last call version, 23 january 2003 >>This comment was mailed earlier to the WebOnt WG [1]. > >For the record, the editor accepts these as editorial comments. > >> >>Consideration of rdfs-entailments from the empty RDF graph >>shows that there is an error in the RDFS entailment lemma. >>In line with the definition in 3.3, one triple >>should be entailed for each of the 13 entries following >>"IC contains": >> rdfs:Resource rdf:type rdfs:Class . >>etc. >>(including a triple >> rdfs:XMLLiteral rdf:type rdfs:Class . >>although rdfs:XMLLiteral does not appear in the table in 3.3) >>and one triple should be entailed for each of the >>entries following "IP contains": >> rdf:type rdf:type rdfs:Property . >>etc. >>Each of these 13 + 16 + aleph-0 triples >>(16 is counted without duplicates; the "aleph-0 triples" are >>from rdf:_1 etc.) follows by using the axiomatic triples in >>combination with the closure rules from 4.2, apart from one >>of these triples: >>The triple >> rdf:value rdf:type rdfs:Property . (*) >>is rdfs-entailed by but is not in the rdfs-closure of the empty >>rdf graph, since rdf:value never appears in either the >>axiomatic triples or the closure rules. > >True. This should be one of the axiomatic triples. This omission was an >editorial oversight. I will correct this. > >> >>(This gives a test case for this problem: >>according to the normative definition, the empty graph >>rdfs-entails the triple (*), but this is not confirmed >>by the rdfs entailment lemma.) >> >>In particular, moreover, each of the 11 triples mentioned >>under part 1. of the definition of rdfs closure >>can safely be omitted from that definition. >>(Note that one of these 11 triples, >> rdf:nil rdf:type rdf:list . >>is already in the definition of rdf closure.) > >Some of the redundancy you refer to has been corrected in the editor's >draft. I will check the patterns you mention below and decide whether or >not to remove any of the redundant conditions. Note however that some >redundancy in the closure rules is harmless and is to be preferred to the >intention being unclear, particularly as this part of the document is >informative. > >Thanks for your detailed comments, in any case. > >Pat > >> >>The following 4 derivation patterns suffice for each >>of these 13 + 15 + aleph-0 proofs >>(This might be added to the proof sketch of the >>rdfs entailment lemma): >>I >> x rdfs:range y . >> rdfs:range rdfs:domain rdf:Property . >> rdfs:range rdfs range rdf:Class . >>together imply >> x rdf:type rdf:Property >> y rdf:type rdf:Class >>II >>similarly for domain instead of range >>III >> rdfs:subClassOf rdfs:domain rdfs:Class . >> rdfs:subClassOf rdfs:domain rdfs:Class . > >You mean rdfs:range in one of these, I assume. > >> x rdfs:subClassOf y . >>together emply >> x rdf:type rdfs:Class . >> y rdf:type rdfs:Class . >>IV >>similary for subPropertyOf instead of subClassOf >> >>(For the proofs involving rdf:_1 etc. also the triples from >>part 2. of the definition of rdfs closure are used.) >> >>Herman ter Horst >>Philips Research >> >>[1] http://lists.w3.org/Archives/Public/www-webont-wg/2003Feb/0313.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 Tuesday, 25 February 2003 09:37:40 UTC