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 --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---