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Re: RDF Semantics - Definition of "Interpretation" is missing (ISSUE-159)

From: David Booth <david@dbooth.org>
Date: Sat, 12 Oct 2013 10:54:27 -0400
Message-ID: <525962A3.9050305@dbooth.org>
To: public-rdf-comments <public-rdf-comments@w3.org>
Some further elaboration . . .

Section 4 of the RDF Semantics does indeed use the term:
[[
The words denotes and refers to are used interchangeably as synonyms for 
the relationship between an IRI or literal and what it refers to in a 
given **interpretation**,
]]

and in Section 5:
http://www.w3.org/TR/2013/WD-rdf11-mt-20130723/#simple
[[
This section defines the basic notions of interpretation
]]

and:
[[
Semantic extensions may impose further constraints upon interpretation 
mappings by requiring some IRIs to refer in particular ways. For 
example, D-interpretations, described below, require some IRIs, 
understood as identifying and referring to datatypes, to have a fixed 
interpretation.
]]

and in Section 5.3:
http://www.w3.org/TR/2013/WD-rdf11-mt-20130723/#simple-interpretations
[[
Following standard terminology, we say that I satisfies E when 
I(E)=true, that E is satisfiable when an **interpretation** exists which 
satisfies it,
]]

There are *many* unqualified uses of the term "interpretation" in the 
RDF Semantics.  If you search you will easily see them.  Even if most of 
those instances were mistakes, the general notion of an interpretation 
is still used throughout the RDF Semantics even if it is not named as 
such.  Throughout the RDF Semantics, an X-interpretation is an 
interpretation that obeys the X semantic constraints (for various X's). 
  In essence, the semantic constraints are hard-coded into the names of 
the various kinds of interpretations: D-interpretation, RDF 
interpretation, etc.  But conceptually at least, the semantic 
constraints could have been factored out, with only generic notions of 
interpretation, entailment, satisfiable, unsatisfiable, valid, invalid, 
etc. defined, all parameterized by the semantic constraints that are 
being used.  (My guess is that it would have been better to write the 
semantics that way, but: (a) I didn't write them, so maybe there's some 
reason I'm wrong; and (b) I know it takes a lot of work to write such 
formal semantics, so I wouldn't want to ask anyone to rewrite them at 
this point.)  But the point is that the general notion of an 
interpretation is used throughout, whether or not it is named as such.

BTW, it is unfortunate that the RDF Semantics spec uses the term "RDF 
interpretation" for the specific kind of interpretation defined in Section 8
http://www.w3.org/TR/2013/WD-rdf11-mt-20130723/#rdf-interpretations
because it means that *outside* of the RDF Semantics spec, the term "RDF 
interpretation" becomes ambiguous: it could mean the specific notion of 
interpretation defined in section 8, or it could mean the *generic* 
notion of interpretation that is used in the RDF semantics, as described 
above.  This is unfortunate, since I often refer to the latter sense. 
But my feeling is that, although this is unfortunate, it probably does 
not cause enough problems to be worth changing the spec over it.

David

On 10/11/2013 11:42 AM, Peter F. Patel-Schneider wrote:
> Hi David:
>
> The RDF working group has received your comment, and is tracking it as
> our ISSUE-159.
>
> You should be receiving an official reply in a short while.
>
> Peter F. Patel-Schneider
> for the RDF working group
>
> On 10/09/2013 07:41 PM, David Booth wrote:
>> Regarding
>> http://www.w3.org/TR/2013/WD-rdf11-mt-20130723/
>>
>> Section 4 of the RDF Semantics is careful to define all of the major
>> terms that are used within the document . . . except one. AFAICT, the
>> general notion of an "interpretation" is nowhere defined.  Later in
>> the document, specific kinds of interpretations are defined, such as
>> Simple Interpretations, RDF Interpretations and RDFS Interpretations.
>> But AFAICT a definition of the general notion of an interpretation is
>> completely absent.
>>
>> The 2004 version of the semantics had a very nice explanation of the
>> notion of interpretations:
>> http://www.w3.org/TR/2004/REC-rdf-mt-20040210/#interp
>> and it had a glossary definition of the term:
>> http://www.w3.org/TR/2004/REC-rdf-mt-20040210/#glossInterpretation
>>
>> I don't know why the current draft eliminated those sections, but
>> somehow the RDF Semantics needs to explain what is meant by an
>> "interpretation", since the notion is central to the semantics.
>>
>> I would suggest restoring the explanation from the 2004 version, but I
>> would be fine with some other replacement instead.
>>
>> Thanks,
>> David
>>
>
>
>
>
Received on Saturday, 12 October 2013 14:54:54 UTC

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