Cause of the slight difference between an elliptic curve and it's minimal model we have the some inconsistent behavior in sage as shown at the end of this post.
I think this behaviour is lightly confusing, and error prone. I think that in this case E.has_good_reduction(5) should return false because you are asking about the reduction type of this specific model of the elliptic curve and not of it's minimal model. The current behaviour is will alway's be available via E.local_data(5).has_good_reduction(). Are there any other people with thoughts about this? Thanks in advance, Maarten Derickx sage: E=EllipticCurve([5^4,5^6]) sage: E.has_good_reduction(5) True sage: E.reduction(5) --------------------------------------------------------------------------- AttributeError Traceback (most recent call last) /Users/maarten/<ipython console> in <module>() /Applications/sage-4.6.rc0/local/lib/python2.6/site-packages/sage/ schemes/elliptic_curves/ell_rational_field.pyc in reduction(self, p) 3358 disc = self.discriminant() 3359 if not disc.valuation(p) == 0: -> 3360 raise AttributeError, "The curve must have good reduction at p." 3361 return self.change_ring(rings.GF(p)) 3362 AttributeError: The curve must have good reduction at p. -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
