Re: A different definition of MINUS, Part 3
Date: Fri, 19 Dec 2008 12:54:12 -0800
Message-ID: <ZQT2l.9484$bZ5.8423_at_newsfe02.iad>
Cimode wrote:
> On 19 déc, 19:37, paul c <toledobythe..._at_oohay.ac> wrote:
>> Cimode wrote:
>>> [Snipped example]
>>> <<As soon as they started
>>> making premises, they lost me because it doesn't look like their
>>> method is anything more than case analysis that have any chances to
>>> be
>>> scaled up to practical problems. >>
>>> Precisely. I would go further as to say that hoping that using solely
>>> algebra would be sufficient to achieve such resultis nothing more than
>>> the holy graal of RL. As you mentionned in an earlier post, the
>>> example of lack of quantifiersi is one major obstacle most current
>>> DandD work seem to ignore without consequence or awareness of the
>>> price to pay.
>>> Regards.. .
>> I think around 1972 Codd wrote a proof that the algebra was logically >> equivalent to FOPC, later others (I forget their names) corrected a few >> errors and proved the equivalence. This is why I'm happy to try to show >> things with the algebra, even though it can be tedious trying to see the >> forest for the trees. > > To my knowledge, Codd never mentionned that FOPC would be sufficient > to clarify RL. Choosing to work *solely* on that angle is a matter of > personal choice. > > Regards...
I don't think that's what I said. I think Codd meant that his relational model obeyed (ie., is based on) both of FOPC and his algebra. The personal choice is whether one uses algebra or fopc not only to understand his model but to define it. Received on Fri Dec 19 2008 - 21:54:12 CET