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Topic: Work on Basic Mathematica Stephen!
Replies: 81   Last Post: Jun 4, 2013 5:59 AM

 Messages: [ Previous | Next ]
 Richard Fateman Posts: 1,539 Registered: 12/7/04
Re: Applying Mathematica to practical problems
Posted: Jun 1, 2013 6:07 AM

On 5/31/2013 12:16 AM, Andrzej Kozlowski wrote:
> Excuse me? I have always assumed that every number system has at least
> one finite number x such that x+1=x, this follows from the group
> axiom. Also, by the way, if we are talking about group addition then
> "x ==0 and x+1 == x" is a not very economical way to express
> x==0.

I think that Andrzej is misreading/ miswriting...

It is fine to have an element x such that x+1=1. That
number is the identity under addition, or zero.

It is not ok to have an element such that x+1=x.

(When x and 1 are supposed to be modeling the real numbers).

As for the rest of the attacks...

z = 1.11111111111111111111;While[(z = 2*z - z) != 0, Print[z]]

Well, see it for yourself (in Mathematica 9) and decide if anyone would
find it so confusing.

Mathematica 9 has adopted my suggestion that numbers with no precision
be displayed differently (in a red box). Prior versions (up to 7 or 8?)
just displayed 0.

Andrzej misconstrues my comments principally in the sense that he
assumes I think it is OK to have a design that gives naive users wrong
answers if it is possible for a skilled user to bypass the
potential disasters by switching arithmetic (etc.)

No, it is a bad design.

The rest of Andrzej's comments are, I think not worth responding to.

Date Subject Author
5/12/13 David Park
5/14/13 Nasser Abbasi
5/15/13 szhorvat@gmail.com
5/16/13 szhorvat@gmail.com
5/16/13 Dr. Peter Klamser
5/17/13 Andrzej Kozlowski
5/17/13 Murray Eisenberg
5/17/13 Dr. Peter Klamser
5/18/13 Dr. Peter Klamser
5/19/13 Murray Eisenberg
5/19/13 paulmchale7@gmail.com
5/19/13 paulmchale7@gmail.com
5/23/13 szhorvat@gmail.com
5/24/13 David Park
5/20/13 Ingolf Dahl
5/20/13 David Annetts
5/22/13 mathgroup
5/23/13 Richard Fateman
5/24/13 W. Craig Carter
5/23/13 David Park
5/23/13 mathgroup
5/24/13 Richard Fateman
5/25/13 David Park
5/25/13 Richard Fateman
5/25/13 David Park
5/28/13 Alexei Boulbitch
5/28/13 Alexei Boulbitch
6/4/13 Bill Rowe
5/24/13 David Park
5/27/13 Noqsi
5/28/13 Richard Fateman
5/31/13 David Bailey
6/1/13 Richard Fateman
6/2/13 David Bailey
6/3/13 Richard Fateman
6/3/13 David Bailey
6/4/13 Andrzej Kozlowski
5/29/13 fd
5/30/13 Noqsi
5/31/13 Richard Fateman
5/31/13 Kevin J. McCann
5/31/13 Andrzej Kozlowski
6/1/13 Richard Fateman
6/1/13 Richard Fateman
6/2/13 Andrzej Kozlowski
6/3/13 Richard Fateman
6/3/13 Andrzej Kozlowski
6/1/13 Daniel Lichtblau
6/2/13 Richard Fateman
6/2/13 James Stein
6/3/13 waku
6/3/13 Daniel Lichtblau
5/27/13 Noqsi
6/2/13 David Bailey
5/28/13 fd
5/31/13 David Bailey
5/28/13 fd
6/2/13 Mark McClure
6/3/13 Richard Fateman
6/3/13 Joseph Gwinn
6/3/13 lshifr@gmail.com
6/3/13 lshifr@gmail.com