On Monday 26 March 2007 1:02 pm, David Harvey wrote: > On Mar 26, 2007, at 3:57 PM, Timothy Clemans wrote: > > Apparently I was incorrectly defining x as an integer, however, I did > > not get an error the first I tried. > > > > incorrect way: x = PolynomialRing(ZZ) > > correct way: g.<x> = PolynomialRing(ZZ) > > > > The len method works now. Thanks. > > Be careful though: > > sage: R.<x> = PolynomialRing(ZZ) > > sage: f = 2*x^2 + 4*x + 8 > > sage: f.factor() > 2 * (x^2 + 2*x + 4) > > sage: len(f.factor()) > 2
Which might actually be what one wants, since indeed your poly f is not "prime" as an element of ZZ[x], since (2) is a prime ideal and (x^2+2*x+4) is divisible by other prime ideals. Note that there is an is_irreducible() method for polynomials, which correctly deals with the case of a multiple factor: sage: f = (x-1)^2 sage: f.is_irreducible() False sage: len(f.factor()) 1 -- william --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://sage.math.washington.edu/sage/ and http://sage.scipy.org/sage/ -~----------~----~----~----~------~----~------~--~---
