On Thu, Nov 14, 2013 at 01:44:02PM +0100, Jeroen Demeyer wrote: > On 2013-11-14 10:28, Georgi Guninski wrote: > >This appears a bug to me: > I would say it's not a bug. The problem is that your question "does > pol have a zero near 1?" depends on what's hidden in the O(3^5). > > For example: (t-1)^2 - 3^6 does have a zero near 1, but (t-1)^2 - > 3^7 does not have a zero. So the question you asked is not > mathematically well defined. > > And indeed, PARI/GP's documentation ??factorpadic states that the > discriminant of the polynomial should be non-zero modulo the > requested modulus p^r. > > Of course, there is a bug here: Sage should raise an exception > whenever this condition is not satisfied. > > Jeroen. >
FYI your factorization fails, while pari/gp's works: ? pol=(x-1)^2+O(3^5); ? pol %2 = x^2 - 2*x + (1 + O(3^5)) ? factor(pol) %3 = [(1 + O(3^5))*x + (2 + 2*3 + 2*3^2 + 2*3^3 + 2*3^4 + O(3^5)) 2] -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/groups/opt_out.
