Re: Oids
From: VC <boston103_at_hotmail.com>
Date: Wed, 17 Aug 2005 18:14:33 -0400
Message-ID: <3PidnW7PUa1aK57eRVn-jw_at_comcast.com>
Date: Wed, 17 Aug 2005 18:14:33 -0400
Message-ID: <3PidnW7PUa1aK57eRVn-jw_at_comcast.com>
"Vadim Tropashko" <vadimtro_invalid_at_yahoo.com> wrote in message
news:1124313591.089076.276900_at_g47g2000cwa.googlegroups.com...
> vc wrote:
>> According to your own definition, the generalized union is (in terms
>> of the standard RA):
>>
>> 'gu' = union(project( a&b, A), project( a&b, B),
>>
>> where A and B are relations, a and b are their respective sets of
>> attributes, & is the set intersection Applying this definition to
>>
>> '00' 'gu' A, we obtain either 00 or 01.
>
> What is
>
> project({}, A)
>
> ?
>
Projection Received on Thu Aug 18 2005 - 00:14:33 CEST