#8967: Make extensions of general rings work in the same way as they do for
number
fields
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Reporter: fwclarke | Owner: AlexGhitza
Type: defect | Status: needs_review
Priority: major | Milestone: sage-4.5
Component: algebra | Keywords:
Author: | Upstream: N/A
Reviewer: | Merged:
Work_issues: |
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Changes (by mstreng):
* cc: mstreng (added)
Comment:
This patch does what it says. It did however take over a bad habit of
"extension" for number fields. See the examples below, where I think the
behavior of QQ is preferred.
{{{
sage: QQ.extension(x^2-2, ('a', 'b'))
IndexError: the number of names must equal the number of generators
sage: GF(3).extension(x^2-2, ('a', 'b'))
Univariate Quotient Polynomial Ring in a over Finite Field of size 3 with
modulus a^2 + 1
sage: QuadraticField(-1, 'i').extension(x^2 - 2, ('a', 'b'))
Number Field in a with defining polynomial x^2 - 2 over its base field
sage: QQ.extension(x^2 - 2, ('a', QQ))
ValueError: variable names must be alphanumeric, but one is 'Rational
Field' which is not.
sage: GF(3).extension(x^2 - 2, ('a', QQ))
Univariate Quotient Polynomial Ring in a over Finite Field of size 3 with
modulus a^2 + 1
sage: QuadraticField(-1, 'i').extension(x^2 - 2, ('a', QQ))
Number Field in a with defining polynomial x^2 - 2 over its base field
}}}
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/8967#comment:3>
Sage <http://www.sagemath.org>
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