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Re: SQL, related records (quotes)

From: Dan Guntermann <guntermann_at_verizon.net>
Date: Sun, 26 Jun 2005 18:31:38 GMT
Message-ID: <ewCve.4092$4M1.2566@trnddc07>

"Stefan Rybacki" <stefan.rybacki_at_gmx.net> wrote in message news:3i80bkFk955oU1_at_individual.net...
> Dan Guntermann wrote:
>> "Stefan Rybacki" <stefan.rybacki_at_gmx.net> wrote in message
>> news:3i78t2Fk4c3tU1_at_individual.net...
>>
>>>Dan Guntermann wrote:
>>>

<snip>
>> Deesn't non-symmetry simply mean there exists a tuple <child X, parent Y>
>> in hierarchies such that there is no corresponding tuple <child Y, parent
>> X> in hierarchies? This isn't the same as a universal quantifier.
>>
>> No. I still think anti-symmetry in conjunction with non-reflexive holds
>> here. Does the following meet the definition of anti-symmetry that you
>> state above?
>
> anti-symmetry + non-reflexifity = non-symmetry

Ahh. I've seen formal definitions for this in terms of assymetric properties. Non-symmetric is new to me and seems awfully close to "not symmetric." It's not worth getting into quibbles over. I'll take your word for it.

Received on Sun Jun 26 2005 - 13:31:38 CDT

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