kirby urner schrieb:
On Tue, Sep 29, 2009 at 9:15 AM, Gregor Lingl <gregor.li...@aon.at> wrote:
Strategy of escalation? Arms race?


Not so much.  There's nothing on the other side.  Will anyone do this
manually?  Is that what "correctly" means?  More likely they mean
something like "symbolically" which is akin to "just imagining
something without really doing any of the work" (so no contest, I walk
away happy).

The ability to brute force these data points with a self-feedback
circuit governed by various expressions, is for computers and
computers only.  Humans by themselves aren't even in the game.  At the
very least you'll want an abacus, or lowly calculator if you're a nerd
(snicker).
Oh no, when thinking about calculations or even only viewing diverging graphs humans not
only are in the game but are still its main characters.

Since say 5000 years humans have devoloped the concepts of numbers, calculations and algebra. They have discovered, that calculations obey certain algebraic laws like a*(b+c) = a*b + a*c and the like. Finally they have devoloped the concepts of
algebraic structures like rings, fields etc.

The purpose of my script simply is to show, that what we know as real numbers are different things (entities) than what we have invented (using nature an physical phenomena) as machine numbers. These two simply obey different sets of algebraic laws. The distributive law is not valid for machine numbers with the operations + and *. And this statement is true
independent from the setting for getcontext().prec.
(Floating point) machine numbers with + and * do not form a field. To describe their
behaviour you have to devise different algebraic structures.

This is not a gewgaw!

In fact my intentions are much less ambituous. I'd be very glad if even 50 % of my students accepted seriously that the squareroot of two does not equal to 1.41421356237. They do not, regardless of the fact that they are able to multiply this number with itself
by hand (!) and to recognize that  the result  does not equal 2.
from turtle import *
from decimal import Decimal, getcontext
getcontext().prec = 50

k = Decimal('3.9')

N = 250

That's what I meant with (in principle)

Gregor


Yes, I understood.  But what's the principle?

In my curriculum, we worship nature and physical phenomena a lot more,
Usually, e. g. when explaining the butterfly effect (does one use this term in English?), on argues that long-term forecasting the future is impossible because of necessary inaccuracies of the initial values as results of measuements. But look precisely: in the example we talk about, there are no measurements, which can be inaccurate and the initial values are well defined. It's the mathematics of machine numbers which generates - after a sequence of only a few hundred arithmetic operations - results, which are completely senseless (or lack any meaning).
If you don't mind,  ok. But you have to admit it.

That is not the case with ordinary numbers.
so this imaginary thing where you imagine the same curves out to
infinity, but don't actually plot anything, who worthless is that?
A very dangerous argument, in my opinion. Many (if not most) mathematicians agree with the statement that one of the most central concepts of mathematics - and the one concept
which makes mathematics interesting - is the concept of infinity.
If not one had to abandon  a large part of classical mathematics.
To think, people actually get paid for such daydreaming.  Amazing.
Now I stared at this sentence for about 10 Minutes but I can't figure out what you wanted to express exactly with this phrase. Don't know if it is my limited knowledge of the English language, my lack of getting the irony or simply my inability to accept the point of view of the
modern geometrician, who anly accepts as real what he can visualize.

Gregor
Kirby

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