[sage-support] Re: group cohomology for two particular groups
For sage, I do not know, but why not try GAP? It has a package HAP for doing homology computations and it might solve your problem. On Wed, Apr 8, 2009 at 8:16 PM, Ursula Whitcher urs...@math.washington.eduwrote: I'd like to know H^3(G,Z) for two particular finite groups, namely L_2 (7), also known as the Chevalley group PSL(2,F_7), and M_20, a subgroup of the Mathieu group M_24 which is isomorphic to a semidirect product of (Z/2Z)^4 with the alternating group A_5. Is Sage capable of these computations? If so, how do I express these groups (or how should I start trying to express them)? If not, does anyone have a suggestion for a place to look this up, or another computation tool I should use? Thanks! Ursula --~--~-~--~~~---~--~~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~--~~~~--~~--~--~---
[sage-support] Re: group cohomology for two particular groups
Hi David,
On 9 Apr., 00:42, David Joyner wdjoy...@gmail.com wrote:
sage: gap.eval('LoadPackage(hap)')
'true'
1. In my first attempt, I forgot this line.
2. In my second attempt, this line returned 'fail'.
However, it may be that my Sage installation is a little messed up. We
will see.
Best regards,
Simon
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[sage-support] Re: group cohomology for two particular groups
On Apr 8, 11:16 am, Ursula Whitcher urs...@math.washington.edu wrote: I'd like to know H^3(G,Z) for two particular finite groups, namely L_2 (7), also known as the Chevalley group PSL(2,F_7), and M_20, a subgroup of the Mathieu group M_24 which is isomorphic to a semidirect product of (Z/2Z)^4 with the alternating group A_5. Is Sage capable of these computations? If so, how do I express these groups (or how should I start trying to express them)? If not, does anyone have a suggestion for a place to look this up, or another computation tool I should use? Thanks! Ursula Thanks everyone for the quick help! UAW --~--~-~--~~~---~--~~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~--~~~~--~~--~--~---
[sage-support] Re: group cohomology for two particular groups
On Wed, Apr 8, 2009 at 2:16 PM, Ursula Whitcher
urs...@math.washington.edu wrote:
I'd like to know H^3(G,Z) for two particular finite groups, namely L_2
(7), also known as the Chevalley group PSL(2,F_7), and M_20, a
subgroup of the Mathieu group M_24 which is isomorphic to a semidirect
product of (Z/2Z)^4 with the alternating group A_5.
Is Sage capable of these computations? If so, how do I express these
groups (or how should I start trying to express them)? If not, does
sage: G1 = PSL(2,7)
sage: MathieuGroup?
explains
The Mathieu group of degree n.
INPUT:
n -- a positive integer in {9, 10, 11, 12, 21, 22, 23, 24}.
OUTPUT:
-- the Mathieu group of degree n, as a permutation group
sage: G1.cohomology(3,p=0)
computes what you want f the hap package is loaded
(using sage -i gap_packages* - see http://www.sagemath.org/packages/optional/).
For M20, you might want to use GAP directly. See
http://www.gap-system.org/Packages/hap.html
anyone have a suggestion for a place to look this up, or another
computation tool I should use?
Thanks!
Ursula
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[sage-support] Re: group cohomology for two particular groups
On Wed, Apr 8, 2009 at 1:11 PM, David Joyner wdjoy...@gmail.com wrote:
On Wed, Apr 8, 2009 at 2:16 PM, Ursula Whitcher
urs...@math.washington.edu wrote:
I'd like to know H^3(G,Z) for two particular finite groups, namely L_2
(7), also known as the Chevalley group PSL(2,F_7), and M_20, a
subgroup of the Mathieu group M_24 which is isomorphic to a semidirect
product of (Z/2Z)^4 with the alternating group A_5.
Is Sage capable of these computations? If so, how do I express these
groups (or how should I start trying to express them)? If not, does
sage: G1 = PSL(2,7)
sage: MathieuGroup?
explains
The Mathieu group of degree n.
INPUT:
n -- a positive integer in {9, 10, 11, 12, 21, 22, 23, 24}.
OUTPUT:
-- the Mathieu group of degree n, as a permutation group
sage: G1.cohomology(3,p=0)
computes what you want f the hap package is loaded
(using sage -i gap_packages* - see
http://www.sagemath.org/packages/optional/).
Just for the record it is impossible to install the optional Gap
packages into SAge-3.4, because
the optional Gap spkg that is posted is:
gap_packages-4.4.10_6
and the current version of GAP in Sage is 4.4.12.
We will be downgrading GAP to 4.4.10 (since 4.4.12 is broken on
Itanium) for sage-3.4.1 so this problem will go away soon.
For the record, the following workaround seems to allow the GAP
packages to install:
(1) cd to SAGE_ROOT/local/lib
(2) type ln -s gap-4.4.12 gap-4.4.10
(3) Do ./sage -f gap_packages-4.4.10_6
I've done this for sagenb.org, so if you make an account there and try
this it will work:
sage: G1 = PSL(2,7)
sage: G1.cohomology(3,p=0)
Multiplicative Abelian Group isomorphic to C2
William
For M20, you might want to use GAP directly. See
http://www.gap-system.org/Packages/hap.html
anyone have a suggestion for a place to look this up, or another
computation tool I should use?
Thanks!
Ursula
--
William Stein
Associate Professor of Mathematics
University of Washington
http://wstein.org
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[sage-support] Re: group cohomology for two particular groups
On Wed, Apr 8, 2009 at 4:21 PM, William Stein wst...@gmail.com wrote: ... computes what you want f the hap package is loaded (using sage -i gap_packages* - see http://www.sagemath.org/packages/optional/). Just for the record it is impossible to install the optional Gap packages into SAge-3.4, because the optional Gap spkg that is posted is: gap_packages-4.4.10_6 and the current version of GAP in Sage is 4.4.12. The 4.4.12 version is here: http://sage.math.washington.edu/home/wdj/patches/gap_packages-4.4.12_1.spkg A few people have tried it out and it seems to work. The command sage -i http://sage.math.washington.edu/home/wdj/patches/gap_packages-4.4.12_1.spkg works for me. ... -- William Stein Associate Professor of Mathematics University of Washington http://wstein.org --~--~-~--~~~---~--~~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~--~~~~--~~--~--~---
[sage-support] Re: group cohomology for two particular groups
Hi David,
On 8 Apr., 16:33, David Joyner wdjoy...@gmail.com wrote:
and the current version of GAP in Sage is 4.4.12.
The 4.4.12 version is
here:http://sage.math.washington.edu/home/wdj/patches/gap_packages-4.4.12_...
I have gap 4.4.12 in Sage, and I did install your version of
gap_packages. However, hap didn't seem to work:
sage: gap.eval('GroupHomology(SylowSubgroup(MathieuGroup(24),2),6,2)')
---
RuntimeError Traceback (most recent call
last)
...
RuntimeError: Gap produced error output
Variable: 'GroupHomology' must have a value
Is anything obvious going wrong?
Cheers,
Simon
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[sage-support] Re: group cohomology for two particular groups
sage: gap.eval('LoadPackage(hap)')
'true'
sage: gap.eval('GroupHomology(MathieuGroup(12),2,2)')
'[ 2 ]'
sage: gap.eval('G:=SylowSubgroup(MathieuGroup(12),2)')
'Group([ (1,2)(3,7)(4,5)(8,11), (1,2)(3,7)(6,12)(9,10), \n
(1,2)(6,9)(8,11)(10,12), (1,2)(3,7)(4,8,5,11)(6,10,12,9), \n
(1,3)(2,7)(4,8)(5,11)(6,9)(10,12), (1,4)(2,5)(3,11)(6,9)(7,8)(10,12)
])'
sage: gap.eval('GroupHomology(G,2,2)')
'[ 2, 2, 2, 2, 2, 2 ]'
sage: gap.eval('GroupHomology(G,6,2)')
'[ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
2, 2, 2, \n 2, 2, 2 ]'
This is in 3.4 immediately after loading gap_packages 4.4.12 from the internet.
On Wed, Apr 8, 2009 at 4:58 PM, simon.k...@uni-jena.de wrote:
Hi David,
On 8 Apr., 16:33, David Joyner wdjoy...@gmail.com wrote:
and the current version of GAP in Sage is 4.4.12.
The 4.4.12 version is
here:http://sage.math.washington.edu/home/wdj/patches/gap_packages-4.4.12_...
I have gap 4.4.12 in Sage, and I did install your version of
gap_packages. However, hap didn't seem to work:
sage: gap.eval('GroupHomology(SylowSubgroup(MathieuGroup(24),2),6,2)')
---
RuntimeError Traceback (most recent call
last)
...
RuntimeError: Gap produced error output
Variable: 'GroupHomology' must have a value
Is anything obvious going wrong?
Cheers,
Simon
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