[GAP Forum] Cohomology of nontrivial G-modules?

Dima Pasechnik dmitrii.pasechnik at cs.ox.ac.uk
Wed Nov 11 21:30:01 GMT 2015


On Wed, Nov 11, 2015 at 11:37:39AM -0500, Benoit Jacob wrote:
> On Wed, Nov 11, 2015 at 11:34 AM, Dima Pasechnik <
> dmitrii.pasechnik at cs.ox.ac.uk> wrote:
> 
> > On Wed, Nov 11, 2015 at 10:52:29AM -0500, Benoit Jacob wrote:
> > > I need to compute cohomology groups of the form
> > >
> > >     H^n(G, A)
> > >
> > > where G is a finite group and A is a nontrivial G-module. More
> > > specifically, A is a finite-dimensional vector space over Z/2Z on which G
> > > acts non-trivially.
> > >
> > > Any example code would be greatly appreciated; I searched for existing
> > help
> > > and documentation but only found examples dealing with trivial G-modules.
> >
> > did you look at GAP's packages? E.g.
> > http://gap-system.org/Packages/hap.html
> > seems to be just what you need.
> >
> 
> Thanks for the answer. HAP does seem like just what I need, but, being a
> GAP beginner, I need something more pedestrian than the functions reference
> documentation I see there. Is there any self-contained example code going
> through the steps of defining a G-module, then computing its cohomology?

did you look at http://hamilton.nuigalway.ie/Hap/www/ ?
(it's more or less the 1st link on http://gap-system.org/Packages/hap.html)
It has a section called Tutorial.

HTH,
Dima



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