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## [Axiom-developer] [Axiom-mail] (new) complex numbers

**From**: |
Bill Page |

**Subject**: |
[Axiom-developer] [Axiom-mail] (new) complex numbers |

**Date**: |
Wed, 29 Dec 2004 00:37:16 -0600 |

On Wednesday, December 29, 2004 1:17 AM Bob McElrath wrote:
>* *
>* Andrea Bedini address@hidden wrote:*
>* > Hi,*
>* > I'm just learning how to do some computations with Axiom,*
>* > but I've a problem with complex numbers.*
>* > *
>* > Why this evalutate to zero ?*
>* > *
>* > (199) -> A: Complex Polynomial Integer*
>* > *
>* Type: Void*
>* > (200) -> A*conjugate A - A^2*
>* > *
>* > (200) 0*
>* *
>* Definitely wrong. It looks like the source of the problem is:*
>* *
>* (18) -> conjugate(a)*
>* *
>* (18) a*
>* Type: Complex Polynomial Integer*
>* *
Of course I agree that it is wrong. But what would you expect
the answer to be?
conjugate(a)
could return unevaluated as just
conjugate(a)
but then what should the Type: be? Is such an expression
still necessarily a Complex Polynomial Integer?
This is dangerously close to the discussion that we had some
months ago about the meaning of "indeterminants", objects
which have a type but no specific value. For example, I can
say
A:Integer
but if I write
A+1
If you answered "yes" to the idea that conjugate(a) is still
of type Complex Polynomial Integer, then surely A+1 is still
of type Integer is the same sense, but Axiom complains that
"A has not been given a value".
Perhaps evaluating the expression
conjugate(a)
should also complain about the lack of a value?
Regards,
Bill Page.
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**[Axiom-developer] [Axiom-mail] (new) complex numbers**,
*Bill Page* **<=**