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Re: Sloppy inference rules

From: Jan Wielemaker <J.Wielemaker@vu.nl>
Date: Thu, 22 Nov 2012 09:26:03 +0100
Message-ID: <50ADE19B.2070202@vu.nl>
To: Tim Berners-Lee <timbl@w3.org>
CC: Pat Hayes <phayes@ihmc.us>, <nathan@webr3.org>, Richard Cyganiak <richard@cyganiak.de>, Guus Schreiber <guus.schreiber@vu.nl>, RDF WG <public-rdf-wg@w3.org>
I guess we should not (re)start this discussion unless there is
a concrete proposal to introduce strings as subjects.   My quick
intuition is that these are a few of the consequences that I don't
like.

   - Invites for poor modelling
   - Introduces interoperability issues
   - Harms efficient reasoning.  One of the nice things about
     resources is that you can compare them quickly.  SPARQL
     Lit1 = Lit2 is a much more complicated beast.

	--- Jan


On 11/21/2012 08:05 PM, Tim Berners-Lee wrote:
>
> Literals in the *subject* position, on the other hand -- are very sensible.
> I have listed reason for these before, and the discussion must be very
> old so I'm
> not inclined to go into them in great depth.
>
> "Fr."  :isShortFor  "France".
>
> 3  expressedAsAString  "3".
>
> 12  :mutuallyPrime 35.
>
> "chat"  :occursIn   :English, :French.
> Also we have inverses, which make any asymmetry
> in what can be put in S and O positions lead to strange things,
>
> :foo  :seconds 73.
> :second owl:inverse :hertz.
>
> for example can be said but leads to an inference which
> cannot be expressed if you can't put a number as a subject.
>
> Tim
>
> On 2012-11 -19, at 13:20, Jan Wielemaker wrote:
>
>> On 11/19/2012 07:13 PM, Pat Hayes wrote:
>>> How about literals in subject position in a triple?
>>
>> I think it is the same story.  Invites for
>>
>> "Paris" something:catipalOf "France"
>>
>> While we all know there are other ways to interpret
>> "Paris".
>
> Yes, but I think your example makes clear:
> What on earth makes you suppose form this example that
> there is any difference between the needs for subject and the needs for
> objects?
>
> Clearly, by this thinking,  literals should due dial allowed in the
> object position too!
>
>
>
>
>
>>  I think we are doing right to allow for
>> literals only in the object position.
>>
>> Cheers --- Jan
>>
>
Received on Thursday, 22 November 2012 08:26:25 GMT

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