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Re: [Axiom-mail] A little simplification problem

From: Themos Tsikas
Subject: Re: [Axiom-mail] A little simplification problem
Date: Mon, 4 Aug 2008 09:44:09 +0100
User-agent: KMail/1.9.6 (enterprise 20070904.708012)

Why? I didn't write the code but my best guess is that such rules would slow 
things down dramatically if they had to be applied everytime there's a "+" 
or "-" or "*" in Expression. You could experiment with your own Expression 
domain, adding more simplification rules and attaching them to the basic 
arithmetic ops. The current Expression implementation relies on the use 
of "normalize"  for when you want to eliminate algebraically redundant 
kernels (informally, subexpressions). There's still the question of why 
does "simplify" not call "normalize". I don't know the answer.

Themos Tsikas

On Saturday 02 August 2008, Alasdair McAndrew wrote:
> Thank you!  In fact the rule
> expandPowers := rule x^(n+k) == x*x^(n+k-1)
> also seems to work well.  But why does Axiom not automatically apply this
> rule for simplification of expressions involving powers, as other CAS's
> (Maple, Maxima, Mathematica) do?
> Thanks again,
> Alasdair
> On Sat, Aug 2, 2008 at 12:41 AM, Themos Tsikas <address@hidden> wrote:
> > On Friday 01 August 2008, Alasdair McAndrew wrote:
> > > f(n)==7^n
> > > f(n+1)-7*f(n)
> > > simplify(%)
> >
> > normalize %

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