W3C home > Mailing lists > Public > w3c-rdfcore-wg@w3.org > January 2002

Datatyping Summary V3

From: Brian McBride <bwm@hplb.hpl.hp.com>
Date: Thu, 31 Jan 2002 17:53:46 +0000
Message-Id: <5.1.0.14.0.20020131173238.02c91d58@0-mail-1.hpl.hp.com>
To: RDF Core <w3c-rdfcore-wg@w3.org>
An updated summary of the datatyping issues, as I currently understand them.

Changes:

   B4 non-entailment confirmed but significance disputed
   'extended n-triples' dropped
   B9 - simple self entailment example added

Issue B1:
=========

In S, if one wants to use both idiom A and idiom B, e.g.

<mary> <age> "10" .
<age> <rdfs:range> <xsd:integer.lex> .

and

<mary> <ageD> _:a .
_:a <xsd:integer.map> "10" .

two properties have to be used, <age> and <ageD>, in this example.

I believe there is a agreement that this is a difference between the
two proposals. Indeed, it may be said that the main aim of TDL is
to avoid requiring different properties for these different idioms.

Can't Live With: PatrickS


Issue B2: Multiple Lexical Representations of a data value
==========================================================
S, idiom A, permits multiple lexical representations of a data value:

_:i <xsd:double> "10.1" .
_:i <xsd:double.de> "10,1" .

I believe there is agreement that S-A allows this.

No-one has said this is a can't live with, so I'm proposing to drop this. 
Going, going, ...

Issue B3: the self entailment issue
===================================
Withdrawn in favour of B4:

From:

http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2002Jan/0410.html

[[I accept the reasoning above; it doesn't address my objection;
it' just shows that my example wasn't very good. Sergey's
example makes the point better:]]

B9 also added in response to Graham's request.


Issue B4 - TDL breaks existing code
===================================
This is similar to B3. I've changed the example slightly from Sergey's.

Under TDL, consider the graph:

_:f <rdf:type> <film> .
_:f <dc:Title> (_, "10") .
<mary> <age> (_, "10").

Does this entail:

_:x <dc:Title> _:y .
_:z <age> _:y .

I believe there is agreement that it does not under the current TDL model 
theory, or the new one proposed by Jeremy on 31/01/2002.

The significance of this is disputed.

Can't Live With: DanC


Issue B5: Storage Requirements
===============================
TDL requires significantly more storage to implement.

This is disputed.


Issue B6: S requires 4 URI's be registered for each data type
=============================================================
S requires that for each datatype 4 URI's be registered
datatype
datatype.lex
datatype.val
datatype.map

Sergey: Do you agree this is the case? If not, how many URI's are required 
to implement ALL the idioms of S and coexist in the same model.


Issue B7: Complexity
====================
S has too many ways of expressing the same thing. An RDF processor has to 
be aware of them all. Supported by Jeremy's error cases message

   http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2002Jan/0397.html

and a message from Andy Seaborne to rdf comments:

   http://lists.w3.org/Archives/Public/www-rdf-comments/2002JanMar/0058.html


Issue B8: S-B encourages logically (sic) errors in the
application type processing.
=======================================================
Given:

_:f <rdf:type> <film> .
_:f <dc:Title> "10" .
<mary> <age> "10" .

an application 'knows' that the range of <age> is an integer so it 'knows' 
that mary has <age> 10. Under S-B, running a query:

?x <dc:Title> ?y .
?z <age> ?y .

will return ?x = _:f and ?z = <mary>, and knowing that the age of <mary> is 
10, may conclude that the title of the film is also 10.

Can't Live With: Jeremy


Issue B9: In TDL a document does not entail itself
==================================================

Under TDL, does:

   <foo> <dc:Title> "W3C" .

entail

   <foo> <dc:Title> "W3C" .

This was recognized as a bug in the TDL model theory.

Can't Live with:  DanC, JJC, GK

Jeremy has proposed a model theory fix:

   http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2002Jan/0464.html

GK, DanC, PatH: do you accept the fix and a document does entail itself 
under TDL?
Received on Thursday, 31 January 2002 12:54:57 EST

This archive was generated by hypermail pre-2.1.9 : Wednesday, 3 September 2003 09:44:04 EDT