fricas
(1) -> factor ((y-1) * x + y - 1)
- is right
\label{eq1}{\left(x + 1 \right)}\ {\left(y - 1 \right)}
(1) Type: Factored(Polynomial(Integer))
fricas
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...
Martin
I think we can close this issue. Are you agree ?
Status: open => closed
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