Re: A different definition of MINUS, part 4
From: Bob Badour <bbadour_at_pei.sympatico.ca>
Date: Tue, 30 Dec 2008 23:58:30 -0400
Message-ID: <495aede8$0$5496$9a566e8b_at_news.aliant.net>
>> On 28 déc, 14:56, paul c <toledobythe..._at_oohay.ac> wrote:
>> [Snipped]
>> <<I'm not sure that this is anything really different from saying that
>> we want logical consistency to be demonstrable in a dbms
>> implementation>>
>> It can not be done without estalishing valid quantifiers for algebric
>> expression or for non algebric expression of RL equations to be
>> resolved. This is one of the aspects I have been trying to underline
>> in previous posts and that is a prerequisite to design a computing
>> model that may allow closure for implementation. In the case of
>> algebric expressions of RL, distance is the most obvious quantifier
>> one can use. But D&D as well as Mc Goveran seem to ignore it.
>>
>> Regards and Merry Christmas to you.
Date: Tue, 30 Dec 2008 23:58:30 -0400
Message-ID: <495aede8$0$5496$9a566e8b_at_news.aliant.net>
> Cimode wrote: >
>> On 28 déc, 14:56, paul c <toledobythe..._at_oohay.ac> wrote:
>> [Snipped]
>> <<I'm not sure that this is anything really different from saying that
>> we want logical consistency to be demonstrable in a dbms
>> implementation>>
>> It can not be done without estalishing valid quantifiers for algebric
>> expression or for non algebric expression of RL equations to be
>> resolved. This is one of the aspects I have been trying to underline
>> in previous posts and that is a prerequisite to design a computing
>> model that may allow closure for implementation. In the case of
>> algebric expressions of RL, distance is the most obvious quantifier
>> one can use. But D&D as well as Mc Goveran seem to ignore it.
>>
>> Regards and Merry Christmas to you.
> > Thanks, mutual. One thing I don't understand about your quantifier > comment; if an algebra has a projection operator, don't we have > quantification in the algebra? (ie., "Exists"?)
I don't understand Cimode's comment either, but it occurs to me that the equals operation for relations provides both quantifiers. Projecting on zero attributes and comparing with DEE gives EXISTS and comparing with a full relation of some sort gives ALL.
Am I missing something? Received on Wed Dec 31 2008 - 04:58:30 CET