Re: Mixing OO and DB

From: Dmitry A. Kazakov <mailbox_at_dmitry-kazakov.de>
Date: Fri, 22 Feb 2008 20:36:05 +0100
Message-ID: <1olhnzcol6vjz.1it2d8rtxcm88.dlg_at_40tude.net>


On Fri, 22 Feb 2008 08:13:10 -0800 (PST), Marshall wrote:

> 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.

mathematical circles = as defined in geometry

> 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;

Of course they do. For example this vanishes:

   forall x, circle exist y, circle twice as big

> 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.

So what? Moreover, forall P, program there exists a unique circle [*]. This does not make programs any circular.


  • Take the binary code of P and write it after "0.". The number obtained is the circle's radius.
-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de
Received on Fri Feb 22 2008 - 20:36:05 CET

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