- From: Graham Klyne <Graham.Klyne@MIMEsweeper.com>
- Date: Fri, 11 Jan 2002 16:07:30 +0000
- To: Patrick Stickler <patrick.stickler@nokia.com>
- Cc: RDF Core <w3c-rdfcore-wg@w3.org>
The implication that _:1 rdf:type xsd:integer.lex . and _:1 rdf:type xsd:integer.val . is only incorrect with respect to the intended interpretation of "xsd:integer.lex" and "xsd:integer.val". The problem is that you made statements which were inconsistent with that intended interpretation (you used ex:age with different-type objects - one from the integer lexical space, and the other from the integer value space). For RDF, it's perfectly legitimate RDFS-entailment, and might quite reasonably be consistent with some different intended interpretation. In a different message to Brian, you said: >The examples I used were based on those given in Sergey's definition >of the A and B idioms. Perhaps there are errors there? Unlike Sergey's similar example, you have used the *same* URI (ex:age) for each idiom. Sergey's examples of A and B use 'exA:birthdate' and 'exB:birthdate', so the problematic entailments do not arise. #g -- At 06:50 PM 1/10/02 +0200, Patrick Stickler wrote: >Sorry if I appear to be in a "slam S" mood today (I'm not, really ;-) >but... > >It appears to me that the S idioms A and B are not compatible >for both local and global typing in the same knowledge base >as are the P and D (and U) idioms. > >If I want to allow for both global and local typing, there >arise problems. E.g. given the following, per idiom B > > Bob ex:age "10" . > ex:age rdfs:range xsd:integer.lex . > >implies, as we desire, that the lexical node "10" is a member >of the class xsd:integer.lex. Fine. > >Now we have, in addition to the above, per idiom A > > Jenny ex:age _:1 . > _:1 xsd:integer.map "22" . > ex:age rdfs:range xsd:integer.val . > >which implies, as we desire > > _:1 rdf:type xsd:integer.val . > >This also apparently could have been inferred from the statement > > xsd:integer.map rdfs:domain xsd:integer.val . > >Again, Fine. > >But taking the first range statement into account along with >the statements about Jenny, we also now have the implication > > _:1 rdf:type xsd:integer.lex . > >which obviously is not correct. > >We also have the unintended (?) implication (though not representable >without P+) that the literal node "10" in the statement about Bob is >of type xsd:integer.val. In P+: > > "10" rdf:type xsd:integer.val . > >Now, maybe it is, and maybe it isn't, but the S specification doesn't seem >to allow a node to be both .lex and .val at the same time. > >What this boils down to is, if the A and B idioms of S trully are not >compatible in the same knowledge base, then S does not appear to provide >a means for both global and local typing in the same environment. > >Comments? Corrections? > >Am I missing something important here??? > >-- > >In comparison, if we define the above knowledge in the P and >D (and U) idioms > > Bob ex:age "10" . > ex:age rdfs:range xsd:integer . > > Jenny ex:age _:1 . > _:1 rdf:value "22" . > _:1 rdf:type xsd:integer . > > Fred ex:age <xsd:integer:47> . > >we have the desired implication about Bob's age > > "10" rdf:type xsd:integer . > >(which of course can't really be represented a such without P+) > >along with (possibly unintended) implications about Jenny's and >Fred's ages, knowledge which we already knew from local definitions, >but nevertheless can be (or may be intended for) use to test for >contraditions > > _:1 rdf:type xsd:integer . > <xsd:integer:47> rdf:type xsd:integer . > >BUT *no* conflicts or undesirable interaction between any of the idioms. > >One additional point: the D idiom (and U) for local typing does not >require *any* global schema information for intepretation, yet >both the A and B idioms of S appear to require schema defined knowledge >for interpretation (or then parsing and interpretation of URIrefs >to look for .lex, .map, etc. suffixes and data type prefixes, etc.). > >-- > >Thus S does not appear to provide a means of fully localized, >schema free, definition of data types for literals, which I >recall was one of the requirements. > >Examples to the contrary are very welcome. > >Cheers, > >Patrick > >-- > >Patrick Stickler Phone: +358 50 483 9453 >Senior Research Scientist Fax: +358 7180 35409 >Nokia Research Center Email: patrick.stickler@nokia.com ------------------------------------------------------------ Graham Klyne MIMEsweeper Group Strategic Research <http://www.mimesweeper.com> <Graham.Klyne@MIMEsweeper.com> __ /\ \ / \ \ / /\ \ \ / / /\ \ \ / / /__\_\ \ / / /________\ \/___________/
Received on Friday, 11 January 2002 11:29:15 UTC