- From: pat hayes <phayes@ihmc.us>
- Date: Mon, 27 Oct 2003 13:19:25 -0500
- To: "Jos De_Roo" <jos.deroo@agfa.com>
- Cc: w3c-rdfcore-wg@w3.org
>[is redirected from rdf-comments to rdf-core] > >Pat - that * suggestion is actually a very good one. >I've done a small test (just this particular case but >it could be generalized to all XML clashes and >maybe also other datatype clashes, but then we >need a bit more time to write code to invoke >XML parsers and/or datatype checkers). >The results are reflected in following proof > >[[ >@prefix iw: <http://www.ksl.stanford.edu/software/IW/spec/iw#>. >@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>. >@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>. >@prefix eg: <http://example.org/eg#>. > { > <http://www.agfa.com/w3c/euler/rdfs-rules#rdfs9>. > {[iw:Variable "?A"] = rdf:XMLLiteral. > [iw:Variable "?B"] = rdfs:Literal. > [iw:Variable "?A"] rdfs:subClassOf [iw:Variable "?B"]} => > {rdf:XMLLiteral rdfs:subClassOf rdfs:Literal}. > { > <http://www.agfa.com/w3c/euler/rdfs-rules#rdfs3>. > {[iw:Variable "?P"] = eg:prop. > [iw:Variable "?C"] = rdf:XMLLiteral. > [iw:Variable "?P"] rdfs:range [iw:Variable "?C"]} => > {eg:prop rdfs:range rdf:XMLLiteral}. > {[iw:Variable "?S"] = eg:foo. > [iw:Variable "?P"] = eg:prop. > [iw:Variable "?O*"] = "<"^^rdf:XMLLiteral. > [iw:Variable "?S"] [iw:Variable "?P"] [iw:Variable "?O*"]} => > {eg:foo eg:prop "<"^^rdf:XMLLiteral}. > [iw:Variable "?S*"] = "<"^^rdf:XMLLiteral. > [iw:Variable "?A"] = rdf:XMLLiteral. > [iw:Variable "?S*"] a [iw:Variable "?A"]} => > {"<"^^rdf:XMLLiteral a rdf:XMLLiteral}. > [iw:Variable "_:Y_3*"] = "<"^^rdf:XMLLiteral. > [iw:Variable "_:Y_3*"] a rdfs:Literal} => >{"<"^^rdf:XMLLiteral a rdfs:Literal}. >]] > >in which you should see 6 occurences of *'ed variables >and an appropriate proof checker is informed that way. > >Till now, I made separate rules to derive inconsistencies >but maybe this way is better; any further thoughts?? I think this way works fine and should extend to datatype clashes in a uniform way, though the derivations there will require datataype savvies of course. The archetype datatype contradiction would be something of the form "literalForm"^^ex:datatype a ex:otherDatatype where the "LiteralForm" cannot denote something in the value space of ex:otherDatatype (for any number of reasons, the most obvious being that it is illtyped for ex:datatype, but in particular cases it could include things like "0.3"^^xsd:real a xsd:integer . where the literal is well-typed in itself, so is a kosher rdfs:Literal, but is an 'illegal' value for the target datatype. I think this is the most general case possible in RDFS+D, but I havn't worked it out in full detail. In OWL you can get other datatype contradictions, eg by defining a subclass of xsd:boolean with three distinct things in it. Pat > >-- >Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/ > > > > > pat >hayes > <phayes@ihmc.us> >To: Jos >De_Roo/AMDUS/MOR/Agfa-NV/BE/BAYER@AGFA > Sent by: >cc: "Peter F. Patel-Schneider" ><pfps@research.bell-labs.com>, > www-rdf-comments-req >www-rdf-comments@w3.org, >www-rdf-comments-request@w3.org > uest@w3.org >Subject: Re: entailment-from-inconsistent-graph >[was: proposed test of RDFS > >entailment >rules] > > > 2003-10-18 03:18 >PM > > > > > > > > > >The current (editor's draft) RDFS rules have a >criterion for detecting inconsistency, to wit, >the derivation of a triple called an 'XML clash'. > >_:nnn rdf:type rdfs:Literal . > >where the subject bnode _:nnn was introduced, and >allocated to an ill-typed literal by, the lg >generalization rule (formerly called rdf2). The >derivation for this example is as follows: > ><http://example.org/prop> ><http://www.w3.org/2000/01/rdf-schema#range> ><http://www.w3.org/1999/02/22-rdf-syntax-ns#XMLLiteral> >. > ><http://example.org/foo> ><http://example.org/prop> >"<"^^<http://www.w3.org/1999/02/22-rdf-syntax-ns#XMLLiteral> >. > ><http://example.org/foo> ><http://example.org/prop> _:1*. rule lg, >with _:1* allocated to >"<"^^<http://www.w3.org/1999/02/22-rdf-syntax-ns#XMLLiteral>, >which is ill-typed. (Jos, can your code keep >track of this when the rule is applied and 'mark' >the bnode accordingly?) > >_:1* ><http://www.w3.org/1999/02/22-rdf-syntax-ns#type> ><http://www.w3.org/1999/02/22-rdf-syntax-ns#XMLLiteral> . rule rdfs3 > ><http://www.w3.org/1999/02/22-rdf-syntax-ns#XMLLiteral> ><http://www.w3.org/2000/01/rdf-schema#subClassOf> ><http://www.w3.org/2000/01/rdf-schema#Literal> . >RDFS axiomatic triple > >_:1* <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> ><http://www.w3.org/2000/01/rdf-schema#Literal> . rule rdfs9 > >So the 'ex cont quod' could reasonably be >restricted to this case, ie if you really believe >an XML clash then you will believe anything. >However, notice that the clash itself is not >inconsistent: it is a symptom of the original set >being inconsistent. So it would not be correct to >say that the silly conclusion is entailed by the >clash; rather, if you can derive a clash from a >graph, then the silly conclusion is entailed by >your original graph. > >>What a coincidence - while sitting in a plane this evening >>I did't think to implement a "ex contradictione quodlibet". >>The premise graphs are assumed to be the case unless they >>can be proven to be inconsistent and then we just say so >>and don't explicitly use them further. So we can't >>run that testcase. > >I think it would be OK to be able to prove the >antecedent inconsistent, and call that a proper >run of the test-case. I think that was Peter's >main point. > >Pat > >> >> >>-- >>Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/ >> >> >> >> > >> Brian >>McBride > >> <bwm@hplb.hpl.hp.com >>To: "Peter F. Patel-Schneider" >><pfps@research.bell-labs.com> >> > >>cc: >>www-rdf-comments@w3.org > >> Sent by: >>Subject: entailment-from-inconsistent-graph >>[was: proposed test of RDFS entailment >> www-rdf-comments-req >>rules] > >> >>uest@w3.org > >> >> > >> >> > >> 2003-10-15 03:37 >>PM > >> >> > >> >> > >> >> >> >> >> >>Peter, >> >>The WG were unable to discuss this suggestion before publishing the 2nd >>last call documents. I propose to track this as a 2nd last call comment: >> >>http://www.w3.org/2001/sw/RDFCore/20031010-comments/#entailment-from-inconsistent-graph > >> >> >>Brian >> >> >> >> >>Peter F. Patel-Schneider wrote: >>> I propose that the following be a positive entailment test in the RDF >>test >>> suite. This is a valid RDFS entailment (modulo typing errors), but is >>not >>> a consequence of the current RDFS entailment rules. >>> >>> Premise >>> >> > <http://example.org/prop> <http://www.w3.org/2000/01/rdf-schema#range> >< >>http://www.w3.org/1999/02/22-rdf-syntax-ns#XMLLiteral> . >>> <http://example.org/foo> <http://example.org/prop> "<"^^< >>http://www.w3.org/1999/02/22-rdf-syntax-ns#XMLLiteral> . >> > >>> Conclusion >>> >>> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> < >>http://www.w3.org/1999/02/22-rdf-syntax-ns#type> < > >http://www.w3.org/1999/02/22-rdf-syntax-ns#type> . >>> >>> >>> Peter F. Patel-Schneider > > >-- >--------------------------------------------------------------------- >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@ihmc.us http://www.ihmc.us/users/phayes -- --------------------------------------------------------------------- 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@ihmc.us http://www.ihmc.us/users/phayes
Received on Monday, 27 October 2003 13:19:39 UTC