Re: <OR> predicate?

On 27/09/2010 1:26 PM, Vadim Tropashko wrote:
> Familiarity is definitely one of the major factors driving adoption.
> Witness the C -> C++ -> Java programming language evolution curve. I
> updated everything. Now at the end of database definition file we have
>
> TABLE_DUM = R00;
> TABLE_DEE = R01;
>
> x<AND> y = x ^ y.
> x<OR> y = (x ^ (y v R11)) v (y ^ (x v R11)).
> (<NOT> x ) = (R11 v x) ^ x'.
>
> Here is DeMorgan law in shiny brand new notation
> (<NOT> x)<OR> (<NOT> y) = (<NOT> (x<AND> y)).
>
> Finally, the assertion you are after is:
> x<OR> (<NOT> x ) = x<OR> TABLE_DEE.
>
> Now I wonder if there are any other pieces left before one can claim
> QBQL as yet another Tutorial D implementation:-)
>

A-algebra projection notation? Just asking, really I should say congrats, best excuse for to enable Java that I've seen in many years. Are there any caveats regarding differences in the various jvms?

(As much as I admire the brainpower behind TTM, much of it goes into aspects that I don't think are essential to elementary RT, but the tiny A-algebra that it all depends on is a really nice piece of thinking, with a 'spec' of just a handful of pages, which I wish more spec's would try to emulate, many others are a size which is inhuman. I always thought it needed an implementation of its own, if only for learning or checking purposes. From comments Hugh Darwen wrote, I believe he originated it and CJ Date polished the definitions, so I think of it as the Darwen and Date algebra, not the other way 'round.) Received on Tue Sep 28 2010 - 03:27:01 CEST