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Re: Inverse properties in Turtle

From: Andy Seaborne <andy.seaborne@epimorphics.com>
Date: Sat, 11 Aug 2012 11:22:14 +0100
Message-ID: <50263256.9030802@epimorphics.com>
To: public-rdf-comments@w3.org
Hi Dan,

On 11/08/12 07:46, Dan Brickley wrote:
> Hi Dave,
>
> On 10 August 2012 19:25, Dave Beckett <dave@dajobe.org> wrote:
>> Dear RDF Working Group
>
> (Just a personal response here)

Ditto.

> Agreed. This is a niche topic, but I still now thing it is of occasional use.
>
> In particular, as a maintainer/editor/contributor for popular RDF
> vocabularies (FOAF, schema.org and others) I believe there is implicit
> demand for this which is often expressed instead in terms of requests
> for new inversely named properties. Whenever someone asks a vocabulary
> maintainer to add 'isDirectorOf' alongside 'director', or asks what
> the inverse of 'actor', or 'associatedAnatomy' or 'depicts' is, they
> are talking about just this issue.

For those people, do you think "^" will read acceptable to those people? 
  (Your point about "isXof" not always being the best choice of name is 
also interesting.)

>> 3. It is not in SPARQL's data syntax.
>> 4. There is a high bar to add a new feature to an existing, well
>>     understood and implemented language like Turtle.  This feature does not
>>     fit that in my judgement.
>
> Taking those two together, ...
>
> I only support adding such a construct if it has a comparable notation
> in SPARQL. They might not be 100% identical, but the basic concept
> ought to either be in both, or in neither. Turtle and SPARQL share a
> common heritage in N3; if we can make teaching them (Turtle and
> SPARQL; I consider N3 something like a "Labs project") easier by
> sharing structure and ideas, we ought to.

A difference between "^:directory" (or the "is...of" syntax) and a 
property :isDirectorOf is that the "^" solution immediately does the 
reversing of the written subject and written object.

:Ridley_Scott ^:director :Blade_Runner

leading to a possible unexpected situation later:

SELECT *
{
    :Ridley_Scott ?p ?o .
}

returns nothing.

	Andy

> cheers,
>
> Dan
>
>> So my request is that you do not add it.
>>
>> Thanks
>>
>> Dave
>>
>
Received on Saturday, 11 August 2012 10:22:44 UTC

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