[GAP Forum] Computing a subgroup of G which does not map i to j
Dima Pasechnik
d.v.pasechnik at uvt.nl
Fri Oct 1 17:30:52 BST 2004
Dear GAP forum
>
On Fri, Oct 01, 2004 at 03:30:04PM +0100, Alastair Donaldson wrote:
> I have the following problem: I have a permutation group G acting on the
> set 1..n, given by a set of generators.
>
> I've discovered that one of the generators of G maps a certain value i to
> a certain value j, and that this is not suitable for my purposes.
>
> I want a subgroup of G which does not map i to j. I could throw away all
> generators that map i to j, but I'd probably lose most of the group then.
the set of elements of G that do not map i to j is not a
subgroup of G.
E.g. the subgroup generated by (ik) and (jk) - note that
these permutations do not map i to j -
contains (ij), that does map i to j
The set of elements of G that fixes i and j is a subgrop, that
can be computed using Stabilizer
HTH,
Dmitrii
http://center.uvt.nl/staff/pasechnik/
More information about the Forum
mailing list