- From: Jos de Bruijn <jos.debruijn@gmail.com>
- Date: Tue, 27 Jul 2010 17:34:57 +0200
- To: Sandro Hawke <sandro@w3.org>
- Cc: RIF <public-rif-wg@w3.org>
Ok, I sent the review directly to the dawg-comments list On Tue, Jul 27, 2010 at 17:20, Sandro Hawke <sandro@w3.org> wrote: > Jos, I think it makes sense to keep this more conversational, and have > you directly reply with this, rather than us discuss it much internally > first. If you agree, please send this to > public-rdf-dawg-comments@w3.org > > -- Sandro > > On Mon, 2010-07-26 at 14:39 +0200, Jos de Bruijn wrote: >> I reviewed the RIF Core entailment section of the current SPARQL 1.1 >> Entailment Regimes draft [1]. Find my comments below. >> >> Major comment (section 7.2): >> I did not understand the definition of Query Answers. It is unclear >> what the combination is for which RIF-Simple entailment is checked. In >> particular, which are the RDF graphs that are considered? Is this just >> the scoping graph or also the graphs imported by the rule set (the >> text in the "Legal Graphs" row seems to sanction such imports). >> >> Errors: >> - Sec 7, 2nd par, 1st sentence: the phrase "...satisfiability and >> entailment, each of which define how a common RIF-RDF interpretation >> is a model of a combination" is incorrect. Satisfiability defines when >> (not how) an interpretation is a model; entailment does not define >> models. >> - Sec 7, 1st par:: >> * It is claimed here that entailment is checked wrt. a >> Skolemization of the scoping graph. This contradicts the definition of >> query answers in Sec. 7.2. >> * It is claimed that only combinations with one RDF graph are >> considered. This seems to contradict the definition of Legal Graphs in >> Sec. 7.2. >> - Sec 7.2, def query answers: rif:imports is not a predicate, it is a CURIE >> - Sec 7.2, "RIF-Core conformance is defined with respect to safe rules >> and so this entailment regime is defined with respect to combinations >> formed from safe RIF documents.": Not true. This entailment regime is >> defined with respect to safe RIF document because it is defined as >> such, in the row "Legal Graphs" of the table. >> - Sec 7.4, 2nd par: cyclic references *do not* rule out the existence >> of a unique minimal model. I believe that every RIF Core document has >> a single unique minimal Herbrand model. Strong safety can, in >> addition, guarantee finiteness (when not considering the datatypes). >> - Sec 7.4, 3rd par: RIF models are necessarily infinite, since the >> domain includes includes all integers. >> >> Further comments: >> - Sec 7.2, 1st editorial note: I wanted to see if I can answer the >> question, but could not find any definition of "answer set" in the >> draft >> - Sec 7.3: I do not understand the relation between the text in this >> section and RIF Core entailment in SPARQL. I see implementation hints >> about RDFS and OWL 2 RL; it seems to me these hints should be included >> in the respective RDFS and OWL 2 RL sections. >> - Sec 7.4, 2nd sentence: I cannot parse '(with possibly infinite)'. >> - Sec 7.4, 2nd par: it is not clear why stratification is discussed >> here, since RIF Core has not negation. In general, I find the >> paragraph a bit confusing. I think it should be rewritten. >> >> Discussion points: >> - I would suggest to remove the rif:imports triple from the scoping >> graph, since it may lead to unexpected inferences. >> >> >> [1] http://www.w3.org/TR/sparql11-entailment/#id35811294 >> >> > > > -- Jos de Bruijn Web: http://www.debruijn.net/ LinkedIn: http://at.linkedin.com/in/josdebruijn
Received on Tuesday, 27 July 2010 15:43:08 UTC