Re: Something new for the New Year (2008).
From: Jan Hidders <hidders_at_gmail.com>
Date: Tue, 8 Jan 2008 02:16:07 -0800 (PST)
Message-ID: <49f1730e-b422-4070-9dd5-38d2e7cb22a5_at_m77g2000hsc.googlegroups.com>
> To be fair, Codd didn't establish the equivalence of expression of the
> algebra and the calculus until his 1972 paper.
Date: Tue, 8 Jan 2008 02:16:07 -0800 (PST)
Message-ID: <49f1730e-b422-4070-9dd5-38d2e7cb22a5_at_m77g2000hsc.googlegroups.com>
On 8 jan, 02:53, Bob Badour <bbad..._at_pei.sympatico.ca> wrote:
>
> To be fair, Codd didn't establish the equivalence of expression of the
> algebra and the calculus until his 1972 paper.
It's a minor detail, but there he didn't actually establish equivalence but just that a certain calculus can be reduced to the algebra, not the other way around, which is what you would need for equivalence. Also the calculus he considers is slightly different from how we nowadays define tuple calculus so I would hesitate to call it *the* calculus. Of course, the insight that is given by the paper was still important for understanding the equivalence, even if it ignored existing work on cylindric algebras that basically said the same.
- Jan Hidders