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## Re: [Axiom-developer] Zero divisors in Expression Integer

**From**: |
Francois Maltey |

**Subject**: |
Re: [Axiom-developer] Zero divisors in Expression Integer |

**Date**: |
18 Jan 2007 22:44:49 +0100 |

**User-agent**: |
Gnus/5.09 (Gnus v5.9.0) Emacs/21.4 |

Hello Waldek,
In this previous mail you write :
>* This is impossible if you want to stay in a single domain.*
>* For example, I freqently use the formula:*
>* *
>* exp(x)-exp(y) = integrate(exp((1-s)*x)*(y-x)*exp(s*y), s=0..1)*
>* *
>* valid when x and y are (no commuting) operators. This formula*
>* would be ruined by usual simplifications of exponentials.*
Do you use the domain Expression for this ?
It seems that domain Expression is commutative for * ?
If so for a student/naive/general/teaching use it's only necessary to
load the naivePackage for the same domain expression.
If we want algebraic rule as you describe an other package over the same
domain will be better.
>* So really each Axiom domain must implement its on simplifications.*
In this case I'm not sure.
>* You are doing nice things with expressions. But have you thought*
>* how your work fits into Axiom design? *
The Question remains.
Francois