Charles Greathouse on Fri, 14 Jun 2024 12:37:57 +0200


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Re: factor(3*x) = x ?!!

I’d just divide by factorback.

On Fri, Jun 14, 2024 at 5:18 AM Markus Grassl <markus.grassl@ug.edu.pl> wrote:
Is there a data type for polynomials with integer coefficients?
Also, is there a way to obtain the unit that is omitted in the list of factors?


Best


Markus

Am 14/06/2024 um 10:37 schrieb Loïc Grenié:
Le ven. 14 juin 2024 à 09:35, <tony.reix@laposte.net> a écrit :
‌Hello,

Is that a bug or a feature ?

(done on Web-GP just now - v2.15.5.28239."6c020b568b". Same on paridroid on my Android smartphone - v2.15.3.2.3. Same on Linux - v2.13.3. Same on Windows - v2.15.4).
 
 
? factor(x)
%2 = Mat([x, 1])
 
? factor(3)
%3 = Mat([3, 1])
 
? factor(3*x)
%4 = Mat([x, 1])

???

    It's a feature. The polynomial is factored in Q[x], and in Q[x] 3 is invertible.

           Hope this helps,

                 Loïc