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Submitted by : (unknown) at: 2007-11-17T22:19:28-08:00 (15 years ago)
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factor ((y-1) * x + y - 1)
is right

\label{eq1}{\left(x + 1 \right)}\ {\left(y - 1 \right)}(1)
Type: Factored(Polynomial(Integer))
factor ((y-1) * sin x + y - 1) -- does nothing

\label{eq2}{{\left(y - 1 \right)}\ {\sin \left({x}\right)}}+ y - 1(2)
Type: Factored(Expression(Integer))

This is "obvious" since EXPR is a field...


I think we can close this issue. Are you agree ?

well documented and more or less mathematically sound --kratt6, Mon, 03 Apr 2006 05:01:02 -0500 reply
Status: open => closed

For others who may find this --daniel, Mon, 08 Jan 2007 20:21:34 -0600 reply
While this is "mathematically sound", it can be very frustrating to new users of Axiom. Is this behavior explained in a FAQ somewhere? Maybe something should be added to section 8.2 of the 30-year book?

To get what the OP wanted, recast the problem as a Polynomial:
f:=(y-1)*sin(x)+y-1 -- original function
g:=subst(f, sin(x)=sx)::Polynomial Integer -- remove the nonlinear operators, then recast
h:=factor(g) -- yields (sx + 1)(y - 1)

Unfortunately, any conversion of h from a "Factored Polynomial Integer" to a "Factored Expression Integer" will destroy the factorization.

Category: Axiom Mathematics => Axiom Library

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