Re: [Axiom-math] How reads axiom Expressions ?

[William Sit]

root wrote:
> 
> Frangois,
> 
> > How can I get (x+1)*(y+1)*(z+1) = x*y*z + x*y + x*z + y*z + x + y + z + 1
> 
> ->n:DMP([x,y,z],FRAC(INT)):=(x+1)*(y+1)*(z+1)
> 
>   x y z + x y + x z + x + y z + y + z + 1
> 
>     Type: DistributedMultivariatePolynomial([x,y,z],Fraction Integer)
> 
> Since "x" is the "highest" variable in the term ordering it is expanded first
> as in
> 
>   x (y z + y + z + 1) + y z + y + z + 1
> 
> and all of the other terms are "constant" with respect to x. In the result
> you gave I can't find a term ordering with similar priority. Your term
> ordering appears to be with respect to term length. There may be a
> metric within DMP that allows that ordering or you could write one.
> 
It seems Francois' expression uses the degree lex term ordering with x > y > z.
In Axiom, the domain is HDMP. You can also define arbitrary term ordering with
GDMP domain. (Just replace DMP above by HDMP; GDMP requires one to supply the
ordering).

William
-- 
William Sit
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