#9390: is_galois_relative() not always right
------------------------------+---------------------------------------------
Reporter: arminstraub | Owner: davidloeffler
Type: defect | Status: needs_work
Priority: major | Milestone: sage-4.6.1
Component: number fields | Keywords: galois extension
Author: Francis Clarke | Upstream: N/A
Reviewer: Marco Streng | Merged:
Work_issues: |
------------------------------+---------------------------------------------
Changes (by mstreng):
* status: needs_review => needs_work
Comment:
Replying to [comment:10 mstreng]:
> The only thing I could think of is that (somewhere in a function called
by
{{{EllipticCurve([1,-1,0,-107,-379]).galois_representation().image_type(7)}}})
an Error of is_galois with degree > 11 is raised and handled in some way.
With your patch, that computation will just go on and on.
Same problem with a fresh install.
Actually, something fishy happens in image_type(7). Without your patch, it
outputs {{{'The image is a group of order 36.'}}} quickly. With your
patch, it goes on and on, until I press Ctrl+C, in which case it catches
my KeyboardInterrupt and outputs {{{'The image is a group of order 36.'}}}
without showing me any Error! So image_type catches all errors, which is
why it stops working with your improvement.
Sorry, but that means this patch can't go in the way it is: either fix
gal_reps or don't touch is_galois.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/9390#comment:11>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
--
You received this message because you are subscribed to the Google Groups
"sage-trac" group.
To post to this group, send email to [email protected].
To unsubscribe from this group, send email to
[email protected].
For more options, visit this group at
http://groups.google.com/group/sage-trac?hl=en.
