ASKSAGE: Sage Q&A Forum - Individual question feedhttp://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Tue, 03 May 2016 17:39:14 -0500.subfields() not working in Sage 6.2; any workaround?http://ask.sagemath.org/question/33311/subfields-not-working-in-sage-62-any-workaround/ Running Sage 6.2, the .subfields() command is not working when applied to an octic number field. Is there any workaround?
(I'm using institutional resources, but they're having trouble updating the Sage version. Hence this question.)
The screenshot is linked below. (Awkward formatting because of the karma system; sorry!)
math.umd.edu/~bloom/sagescreenshot.png
Tue, 03 May 2016 15:20:09 -0500http://ask.sagemath.org/question/33311/subfields-not-working-in-sage-62-any-workaround/Answer by tmonteil for <p>Running Sage 6.2, the .subfields() command is not working when applied to an octic number field. Is there any workaround? </p>
<p>(I'm using institutional resources, but they're having trouble updating the Sage version. Hence this question.)</p>
<p>The screenshot is linked below. (Awkward formatting because of the karma system; sorry!)
math.umd.edu/~bloom/sagescreenshot.png</p>
http://ask.sagemath.org/question/33311/subfields-not-working-in-sage-62-any-workaround/?answer=33314#post-id-33314It should work:
sage: NumberField(x^8-2*x^7+4*x^5-4*x^4+3*x^2-2*x+1,'b').subfields()
[
(Number Field in b0 with defining polynomial x, Ring morphism:
From: Number Field in b0 with defining polynomial x
To: Number Field in b with defining polynomial x^8 - 2*x^7 + 4*x^5 - 4*x^4 + 3*x^2 - 2*x + 1
Defn: 0 |--> 0, None),
(Number Field in b1 with defining polynomial x^2 + 1, Ring morphism:
From: Number Field in b1 with defining polynomial x^2 + 1
To: Number Field in b with defining polynomial x^8 - 2*x^7 + 4*x^5 - 4*x^4 + 3*x^2 - 2*x + 1
Defn: b1 |--> -b^7 + 2*b^6 - 3*b^4 + 3*b^3 - 2*b + 1, None),
(Number Field in b2 with defining polynomial x^4 - 2*x^3 + x^2 + 1, Ring morphism:
From: Number Field in b2 with defining polynomial x^4 - 2*x^3 + x^2 + 1
To: Number Field in b with defining polynomial x^8 - 2*x^7 + 4*x^5 - 4*x^4 + 3*x^2 - 2*x + 1
Defn: b2 |--> -b^7 + 2*b^6 - 4*b^4 + 3*b^3 + b^2 - 2*b + 1, None),
(Number Field in b3 with defining polynomial x^8 - 2*x^7 + 4*x^5 - 4*x^4 + 3*x^2 - 2*x + 1, Ring morphism:
From: Number Field in b3 with defining polynomial x^8 - 2*x^7 + 4*x^5 - 4*x^4 + 3*x^2 - 2*x + 1
To: Number Field in b with defining polynomial x^8 - 2*x^7 + 4*x^5 - 4*x^4 + 3*x^2 - 2*x + 1
Defn: b3 |--> b, Ring morphism:
From: Number Field in b with defining polynomial x^8 - 2*x^7 + 4*x^5 - 4*x^4 + 3*x^2 - 2*x + 1
To: Number Field in b3 with defining polynomial x^8 - 2*x^7 + 4*x^5 - 4*x^4 + 3*x^2 - 2*x + 1
Defn: b |--> b3)
]
If your home directory is sufficiently large, i suggest to install your own recent version of Sagemath until your institution updates it. You do not need to have root access for that. What is the output of the following commands (from a terminal):
uname -a
cat /etc/issue
Tue, 03 May 2016 17:39:14 -0500http://ask.sagemath.org/question/33311/subfields-not-working-in-sage-62-any-workaround/?answer=33314#post-id-33314