> < ^ Date: Sat, 03 May 2003 22:08:06 -0400
> ^ From: J.F. Huesman <QPhysics@yahoo.com >
< ^ Subject: Re: Re: Crystal lattice and cohomology

Fellow GAP Forum members,
I want to thank Franz Gähler and Derek Holt for their help with my problem
of calculating the cohomology of a crystal.
I am, sadly, still having a problem...and I am not sure what it is. This is
now more of a troubleshooting problem, so I'm not sure if this is the proper

```When I enter the following, from Dr. Gähler,
gap> g:=Group([[-1,0,0],[0,-1,0],[0,0,-1]],[[-1,0,0],[0,1,0],[0,0,-1]]);
Group([ [ [ -1, 0, 0 ], [ 0, -1, 0 ], [ 0, 0, -1 ] ],
[ [ -1, 0, 0 ], [ 0, 1, 0 ], [ 0, 0, -1 ] ] ])
gap> gens := GeneratorsOfGroup(G);
[ [ [ -1, 0, 0 ], [ 0, -1, 0 ], [ 0, 0, -1 ] ],
[ [ -1, 0, 0 ], [ 0, 1, 0 ], [ 0, 0, -1 ] ] ]
gap> F := Image( IsomorphismFpGroupByGenerators( G, gens ) );
<fp group of size 4 on the generators [ F1, F2 ]>
as should be the case, I get an error message:
Error the coset enumeration has defined more than 256000 cosets:
type 'return;' if you want to continue with a new limit of 512000
cosets,
type 'quit;' if you want to quit the coset enumeration,
type 'maxlimit := 0; return;' in order to continue without a limit,
at
Error( "the coset enumeration has defined more ", "than ", limit,
" cosets:\ntype 'return;' ", "if you want to continue with a new limit
",
"of ", maxlimit, " cosets,\ntype 'quit;' ", "if you want to quit the
coset "
, "enumeration,\ntype 'maxlimit := 0; return;'",
" in order to continue without a limit,\n" );
TCENUM.CosetTableFromGensAndRels( fgens, grels, fsgens ) called from
CosetTableFromGensAndRels( fgens, grels, fsgens ) called from
TryCosetTableInWholeGroup( H ) called from
CosetTableInWholeGroup( U ) called from
One( G ) called from
...
```

Am I doing something wrong? I am using GAP 4r2 on Windows NT Workstation 4.0
SP6.

Thank you all for any assistance.

John Huesman