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Re: MINUS vs. UNSAID

From: Steve Harris <steve.harris@garlik.com>
Date: Tue, 7 Jul 2009 12:16:04 +0100
Cc: Eric Prud'hommeaux <eric@w3.org>, public-rdf-dawg@w3.org
Message-Id: <3F4816AB-94C2-4D69-8E44-09FCFB59DBA2@garlik.com>
To: Lee Feigenbaum <lee@thefigtrees.net>
On 7 Jul 2009, at 01:58, Lee Feigenbaum wrote:
> Do you mean s/MINUS/UNSAID, I imagine
>
>> Result U3 (extrapolated from UNSAID results above):
>> ?who   ?nam  _:eve  "eve"
>
> If I understand UNSAID correctly, you'd do the above MINUS query as:
>
> ?who foaf:givenname ?name .
> UNSAID {
>  ?who foaf:holdsAccount ?act .
>  ?act foaf:accountName ?name .
> }
>
> "People with a certain name for whom it is unsaid that their account  
> has the same name."
>
> Is that right or wrong?
>
> If it's right, I find (to me) the UNSAID way to be a much more  
> natural way of writing this query - I'm not actually convinced the  
> MINUS version is any clearer than OPTIONAL + !bound :-)

Interesting, I find it easier to get my head around MINUS. For UNSAID  
with OPTIONAL I'd have to map that into a MINUS expression to figure  
out what (if anything) it meant.

- Steve

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Steve Harris
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Received on Tuesday, 7 July 2009 11:16:41 GMT

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