#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 newvalueoldvalue):
* status: needs_review => needs_work
* reviewer: => Marco Streng
* milestone: => sage-4.6.1
* author: => Francis Clarke
Comment:
Nice, that is a lot faster, and correct. There is one thing I don't like
though: you introduced a difference between `is_galois` of absolute number
fields and `is_galois_absolute` of relative number fields:
With your patch on Sage 4.6.1.alpha2:
{{{
sage: M.<c> = NumberField(cyclotomic_polynomial(100))
sage: M
Number Field in c with defining polynomial x^40 - x^30 + x^20 - x^10 + 1
sage: M.is_galois()
NotImplementedError
sage: M.relativize(1, 'd').is_galois_absolute()
True
sage: M.relativize(1, 'd').is_galois_relative()
True
}}}
Without your patch, it is NotImplementedError, NotImplementedError, False,
so your patch is a definite improvement, but could be better.
I think it would be better to put your new code in `is_galois` of absolute
fields instead of `is_galois_absolute` of relative fields. Then
`is_galois_absolute()` can simply call `self.absolute_field().is_galois()`
PS grammar: line 1177 of number_field_rel.py after the patch, previous
should be previously (or simply replace the line by "Check that bug #9390
is fixed::")
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/9390#comment:4>
Sage <http://www.sagemath.org>
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