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reviewing RDF Semantics

From: Jos De_Roo <jos.deroo.jd@belgium.agfa.com>
Date: Thu, 19 Dec 2002 23:02:10 +0100
To: "w3c-rdfcore-wg" <w3c-rdfcore-wg@w3.org>, phayes@ai.uwf.edu
Message-ID: <OFD3F80E9B.115EBD1C-ONC1256C94.00785F6B-C1256C94.00790C32@agfa.be>

Reviewing http://www.w3.org/2001/sw/RDFCore/TR/WD-rdf-mt-20030117/
I can support approval for this great document!
In what follows, I only make non-prohibitive remarks...


| RDF Semantics
| W3C Working Draft 12 December 2002

should actally be
  W3C Working Draft 17 December 2002
but should later maybe
  W3C Working Draft 17 January 2003


| This Version:
|   http://www.w3.org/TR/2002/WD-rdf-mt-20021112/

should actually be
  http://www.w3.org/2001/sw/RDFCore/TR/WD-rdf-mt-20030117/
but should later maybe
  http://www.w3.org/TR/2002/WD-rdf-mt-20030117/


| 0. Introduction

OK


| 1. Interpretations

OK


| 2. Simple entailment between RDF graphs.

OK


| 3. Interpreting the RDF(S) vocabulary
| [...]

very nice Figure 2!


| 3.2.4 rdf:value
| [...]
|
| Since the range of possible uses for rdf:value is so wide,
| it is impossible to give a precise model-theoretic statement
| which covers all the intended meanings or use cases. Users
| are cautioned, therefore, that the use of rdf:value is
| somewhat risky, and that it should be treated as a 'blank'
| piece of RDF syntax whose meaning in any particular case
| should be defined by the user, and may vary from application
| to application. In practice, the intended meaning is often
| clear from the context, but may be lost when graphs are
| merged or when conclusions are inferred.

maybe say that they never contribute to any entailments
or some such


| 3.3.1 A note on rdfs:Literal
| The semantic conditions on rdfs-interpretations do not include
| the condition that ICEXT(I(rdfs:Literal)) must be a subset of LV.
| While this would seem to be required for conformance with [RDFMS],
| there is no way to impose this condition by any RDF assertion or
| syntactic closure rule. This limitation is due to the fact that
| RDF does not allow literals to occur in the subject position of a
| triple, so there are severe restrictions on what can be said about
| literals in RDF. Similarly, while properties may be asserted of
| the the class rdfs:Literal, none of these can be validly
      ^^^
| transferred to literals themselves.

as you know, it seems to me that (at least) typed literals can be
perfect subjects (I really don't see why not)


| 4. Vocabulary entailment and closure rules
| [...]
|
| 4.2 RDFS-entailment and RDFS closures (informative)
| [...]
|
| rdfs 4a' | xxx aaa yyy . | aaa rdfs:domain rdfs:Resource .
|
| rdfs 4b' | xxx aaa yyy . | aaa rdfs:domain rdfs:Resource .

(as I did remark before) those seem to be the same,
but I guess you meant rdfs:range in rdfs4b'


| 4.3 Datatype entailments (Informative)
| [...]
|
| rdfD 1 | ddd rdf:type rdfs:Datatype . | aaa ppp _:xxx .
|        | aaa ppp "sss"^^ddd .         | _:xxx rdf:type ddd .

additionally to that we have also been (succesfully) testing

  rdfD 1b | ddd rdf:type rdfs:Datatype . | ddd rdfs:domain ddd .

  rdfD 1c | ddd rdf:type rdfs:Datatype . | aaa ppp _:xxx .
          | aaa ppp "sss"^^ddd .         | _:xxx ddd "sss" .


| Appendix B: Proofs of lemmas.
| [...]
|
| RDF closure lemma. The Herbrand interpretation of the rdf-closure
|   of E is an rdf-interpretation of E.
| [...]
|
| so HP contains rdf:type, which is H(rdf:type),

I suppose (that) HP (wasn't defined so far) is defined to be the
set of urirefs which occur either as arc labels in the graph,
or as subjects of triples of the form s rdf:type rdf:Property
no?


| Appendix C: Glossary of terms
| [...]
|
| Use (v.) contrasted with mention; to use a piece of syntax
|   to denote or refer to something else. The normal way that
|   language is used.

i.e.
  whenever, in a sentence, we wish to say something
  about a certain thing, we have to use, in this
  sentence, not the thing itself but its name or
  designation -- Alfred Tarski

maybe also mention "mention"

maybe also "paradox"


...I really like the document!!!

-- ,
Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/
Received on Thursday, 19 December 2002 17:02:48 EST

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