Re: Proposal: 6NF

From: David Cressey <>
Date: Thu, 19 Oct 2006 12:14:03 GMT
Message-ID: <f_JZg.5851$Z46.2439_at_trndny05>

"J M Davitt" <> wrote in message news:KnzZg.17032$


> Well, the line must be drawn between what can and cannot be easily
> represented. For instance, it would be tough to handle integers
> in the intervals (-oo, -2^^64] and [2^^64, oo). (Did I get that
> right?) And there's a whole world-full of values that slip
> between one easily representable rational value and the next.

I'm not sure I use the word "easily" the same way you do.

It's not hard to come up with a representation scheme that's "indefinitely extensible". The common base ten number system can represent the successor of any natural number. By induction, there is no upper limit to the numbers that the place value representation scheme can represent.

Incidentally, the number of symbols required for the decimal place value system is actually 11, and not 10.
The ten symbols we all agree on are {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}. The eleventh symbol is "there isn't a digit here" represented by whitespace when you write a number with pencil and paper. This eleventh symbol only needs to be used once, but it is part of the represntation scheme.

Likewise in an ASCII character string in the C language, the character sometimes called NUL only appears once, at the end of the string. This scheme is indefinitely extensible as well.

The relationship between indefinitely extensible schemes and the internet, which is a finite state machine at any point in time but is subject to unlimited growth, is more subtle than most people think it is. Received on Thu Oct 19 2006 - 14:14:03 CEST

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