Re: Mixing OO and DB

From: Marshall <marshall.spight_at_gmail.com>
Date: Fri, 22 Feb 2008 08:13:10 -0800 (PST)
Message-ID: <a81c83e7-ea46-4ad5-9387-d15edf710bf6_at_e10g2000prf.googlegroups.com>


On Feb 22, 3:24 am, "Dmitry A. Kazakov" <mail..._at_dmitry-kazakov.de> wrote:
> On Thu, 21 Feb 2008 20:37:09 -0800 (PST), Marshall wrote:
>
> > Mathematics contains within in the idea of computable
> > functions, computable reals, etc. Computers can of
> > course only compute computable functions. A person
> > with pencil and paper has the same limitation. The
> > person with pencil and paper, drawing a set of equations,
> > using geometry, whatever, is said to be working with
> > circles. Software can work with circles as well.
> > A computer cannot perform calculations on a circle
> > whose center is a pair of uncomputable reals; neither
> > can a person. However a person can recognize the
> > fact that the equations describing circles are special
> > cases of the equations describing ellipses, and a
> > computer can be programmed to take advantage
> > of this as well.
>
> > The distinction between "circle value" and "circle"
> > is without merit: the two terms have identical
> > denotations.
>
> This is an invalid argument. You claim that circles drawn by pencil are
> equivalent to ones in the program. I don't know, but let them be. From this
> does not follow that either is equivalent to mathematical circles.

Since you haven't defined "mathematical circles" I can't evaluate your claim. Earlier your threw around the word "uncountable" a few times so maybe you have some related meaning in mind. But it doesn't matter; if we limit our context to what is computable, then mathematical relationships don't somehow vanish; a computable circle is still an ellipse, just as much as an uncomputable circle is. Also: every countable set of circles is still a subset of the set of all ellipses.

> It is just like to argue that the set of integer is finite because
> you don't know anybody who could count it.

No, it is nothing like that.

Marshall Received on Fri Feb 22 2008 - 17:13:10 CET

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