Re: SQL, related records (quotes)

From: Dan Guntermann <>
Date: Sun, 26 Jun 2005 18:31:38 GMT
Message-ID: <ewCve.4092$4M1.2566_at_trnddc07>

"Stefan Rybacki" <> wrote in message
> Dan Guntermann wrote:
>> "Stefan Rybacki" <> wrote in message
>>>Dan Guntermann wrote:
>> 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.

  • Dan
Received on Sun Jun 26 2005 - 20:31:38 CEST

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