#8751: conversion between non-prime finite fields
--------------------------------+-------------------------------------------
Reporter: zimmerma | Owner: AlexGhitza
Type: defect | Status: new
Priority: minor | Milestone:
Component: basic arithmetic | Keywords:
Author: | Upstream: N/A
Reviewer: | Merged:
Work_issues: |
--------------------------------+-------------------------------------------
I noticed the following with Sage 4.3.5:
{{{
sage: R = GF(9,name='x')
sage: Q.<x> = PolynomialRing(GF(3))
sage: R2 = GF(9,name='x',modulus=x^2+1)
sage: a=R(x+1)
sage: R2(a)
---------------------------------------------------------------------------
TypeError Traceback (most recent call
last)
/users/caramel/zimmerma/svn/sagebook/tex/<ipython console> in <module>()
/usr/local/sage-core2/local/lib/python2.6/site-
packages/sage/rings/finite_field_givaro.so in
sage.rings.finite_field_givaro.FiniteField_givaro.__call__
(sage/rings/finite_field_givaro.cpp:4754)()
TypeError: unable to coerce from a finite field other than the prime
subfield
}}}
This is ok since indeed a=x+1 is not in the prime subfield.
But:
{{{
sage: b=R(1)
sage: R2(b)
---------------------------------------------------------------------------
TypeError Traceback (most recent call
last)
/users/caramel/zimmerma/svn/sagebook/tex/<ipython console> in <module>()
/usr/local/sage-core2/local/lib/python2.6/site-
packages/sage/rings/finite_field_givaro.so in
sage.rings.finite_field_givaro.FiniteField_givaro.__call__
(sage/rings/finite_field_givaro.cpp:4754)()
TypeError: unable to coerce from a finite field other than the prime
subfield
}}}
In this case b=1 ***is*** in the prime subfield!!!
Side question: is there a (simple) way to get the isomorphism between R
and R2?
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/8751>
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.
