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Re: [Axiom-math] How reads axiom Expressions ?
From: |
Dylan Thurston |
Subject: |
Re: [Axiom-math] How reads axiom Expressions ? |
Date: |
Mon, 13 Oct 2003 03:03:21 -0400 |
User-agent: |
Mutt/1.5.4i |
On Mon, Oct 13, 2003 at 08:37:06AM +0200, address@hidden wrote:
> Hello,
>
> I type this example in axiom :
>
> (4) -> (sin (x)+1/2)*(cos(x)+1/2)
> (4cos(x) + 2)sin(x) + 2cos(x) + 1
> (4) ---------------------------------
> 4
>
> I don't understand the result :
> it's _not_ an expanded product, and it's _not_ a factorised product.
> What does axiom ?
I don't think it's specific to sin/cos:
(9) -> (x + 1/2) * (y + 1/2)
1 1 1
(9) (x + -)y + - x + -
2 2 4
Type: Polynomial Fraction Integer
From reading the tutorial, I believe that Axiom by default is writing
this as a polynomial in the variable 'y', which is the lexicographically
largest variable.
Hmm, it seems that here we're probably really seeing the differences
between Axiom's approach and a tree-based approach like in the three Ms.
Axiom seems to be storing this polynomial as a polynomial, and not just
as a tree of expressions; as such, I'm guessing that it is put in a
canonical form using Groebner bases and such.
Peace,
Dylan
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