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Model theory review, thumbs up

From: Graham Klyne <GK@NineByNine.org>
Date: Sat, 09 Nov 2002 14:01:07 +0000
Message-Id: <5.1.0.14.2.20021109114446.03b6deb0@127.0.0.1>
To: Pat Hayes <phayes@ai.uwf.edu>, RDF core WG <w3c-rdfcore-wg@w3.org>

Reviewing [1]:

[1] 
http://lists.w3.org/Archives/Public/www-archive/2002Nov/att-0022/01-RDF_20Model_20Theory_Oct_draft.html

My report to the group is that this is fit to publish.

I would prefer (but don't insist) that 2nd para of section 1.3 is not included.

Other comments below are non-editorial, in the sense that I felt they might 
impact how the document was understood.  But none of them are essential.

...

Section 1.2:

Note that "character string" is a sequence of Unicode characters?

[Later: I see this is mentioned in 0.2]

...

Section 1.4:

Para 2:  following the definition of simple interpretation, I think it is 
the case that there are no practical uses for it (all RDF graphs being 
subject to at least RDF-entailment)?

...

Section 1.4:

5th para states "assume that LV is a subset of IR"

item 2 says:  powerset of IRx(IR union LV)

surely the latter is now redundant, and could read powerset of IRxIR ?

...

Similarly, mention of "y in IR or LV".

...

Section 3.2.1

Para 2 mentions "I(aaa) is a token of an RDF triple"

Para 4 has "when x is an occurrence of an RDF triple with the form"

The latter suggests to me that the RDF triple has to actually *occur* 
somewhere, and some might think that means the graph under 
consideration.  My suggestion is to change the text in para 4 to 
read:  "when x is a token of an RDF triple with the form"

Para 6 also talks about "a triple in a particular RDF document", again 
suggesting the triple actually exists unreified, which I think it may 
not.  (e.g. If my document said "Bill rdf:type ex:Clown" then Bill might be 
upset with me.)  Suggest:  "a occurrence or notional occurrence of a triple 
in a particular representation of an RDF graph".

...

Section 3.2.1

I'm uneasy about trying to tie the intended interpretation of reification 
to a concrete syntax.  In the preceding para, you discuss "apply the 
interpretation mapping again to get the referent...".  Doesn't the 
interpretation mapping apply to the abstract syntax, not a concrete syntax?

...

Section 3.2.3

Final para, "should always describe a linear sequence", reads as if lists 
containing lists are not recommended;  I don't think that's intended, and I 
have used lists in which some of the elements are themselves lists.

...

Section 3.4

Para 3 says "datatype aware RDF engine should ... recognize ... and the set 
of all the XML schema datatypes".  All?  There seems to be a fair bit of 
stuff there that doesn't really apply (e.g. ENTITIES).  I think this could 
be limited to the primitive datatypes 
(http://www.w3.org/TR/xmlschema-2/#built-in-primitive-datatypes), and maybe 
the derived integer types.

...

Section 3.4

The ^^ notation appears here without, as far as I have noticed, any prior 
introduction.

(Section 0.2 introduces typed literals as pairs.)

...

Section 3.4

I observe that the treatment of invalid literals means that one can 
legitimately construct an interpretation in which invalid typed literals 
have useful meanings;  e.g. that a property extension for p might be 
arranged so that whenever:

    s p "10"^^xsd:integer .

is true, then

    s p "ten"^^xsd:integer .

is also true.

(I don't think this is a problem, just observing.)

...

Section 4.3

I find myself uneasy about the lack of any form of entailment lemma for 
datatype closures.

Given that the D-interpretation is defined in terms of a given set D of 
datatypes, it seems to me that it should be possible to define some rules 
in terms of the L2V of those datatypes (which I take to be equivalent to 
"consulting the datatype sources").  I don't have time right now to think 
this through, but it would be interesting to see if there's something more 
satisfying (sic) that can be said here.

...

Appendices not checked.

#g


-------------------
Graham Klyne
<GK@NineByNine.org>
Received on Saturday, 9 November 2002 08:59:17 EST

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