Checking if a polynomial is irreducible: list of factors?
Subject: Checking if a polynomial is irreducible: list of factors?
From: Alasdair McAndrew
Date: Tue, 24 Oct 2006 07:30:40 +1000
What I ended up doing was checking if the highest power in the original
expression was equal to the highest power returned by args:
if hipow(args(factor(p))[1],x)#hipow(p,x) then
and so on. But this seems clumsy. In my ideal Maxima world there would be
a command "factorlist" which produces a list of factors of a polynomial,
similiar to the list returned by "ifactors".
There I go, dreaming again....
Alasdair
On 10/24/06, Richard Fateman <fateman at cs.berkeley.edu> wrote:
>
> How about this:
>
> you count the args, make sure that the answer is not atomic, and the
> main operator is "*" or "^".
>
> Looks like the Maxima mailing list is back.
> RJF
>
>
> Alasdair McAndrew wrote:
>
> > Hi,
> >
> > I'm experimenting with some programs to perform computations in finite
> > fields; one thing I need to do is to determine if a polynomial is
> > irreducible. An easy way to do this would be to count the number of
> > factors returned with the "factor" command, but I don't know how to do
> > this; "args" works differently in each case. For example:
> >
> > (%i1) args(factor(x^2-1));
> > (%o1) [x-1,x+1]
> > (%i2) args(factor(x^2+1));
> > (%o2) [x^2,1]
> >
> >
> >
> >
>
>