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Re: MINUS vs. UNSAID

From: Lee Feigenbaum <lee@thefigtrees.net>
Date: Tue, 07 Jul 2009 09:35:08 -0400
Message-ID: <4A534F0C.70101@thefigtrees.net>
To: Steve Harris <steve.harris@garlik.com>
CC: Eric Prud'hommeaux <eric@w3.org>, public-rdf-dawg@w3.org
Steve Harris wrote:
> 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.

I agree that UNSAID + OPTIONAL is a weird combination; I meant that 
(again, assuming my understanding is correct) that to accomplish the 
goal of the above query with UNSAID -- which doesn't require OPTIONAL -- 
is much clearer to me than to have to figure out the combination of 
MINUS + OPTIONAL that does it correctly.

Lee

> 
> - Steve
> 
Received on Tuesday, 7 July 2009 13:36:07 GMT

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