[GAP Forum] orbits of a set under induced group action

[Abhishek]

Hi John, Sven and Laurent,

Laurent, thanks for pointing out that f's are characteristic functions of X.
I can now solve small problems. But as Sven said I am running into memory
problems when trying to solve large problems.

Sven, thanks for the reference. I am trying to get a copy of it. Since my
library doesn't have a copy of it, it's going to be a few days before I can
get it. I'll probably ask you for your code after I get the paper. Also,
from your comment, I'm guessing that GAP doesn't have any such algorithm
implemented that just finds a representative in each orbit. Did I get this
right?

John, thanks for pointer but unfortunately I have not been able to locate
it. Can you possibly give me a more specific reference?

Regards,
Abhishek


On 4/13/06, MCKAY john <mckay at encs.concordia.ca> wrote:
>
>
> This is I think a standard problem. There is code in
> Collected algorithms of ACM  in ALGOL going back to the
> 60's. Try authors Regener, Soicher if my mempory serves me
> right.
>
> John
>
>
> On Thu, 13 Apr 2006 reichard at maths.uwa.edu.au wrote:
>
> > Hi Abhishek, hi Laurent,
> >
> > the approach described by Laurent works fine if X is reasonably small,
> say
> > up to 20 elements. For larger X (and hopefully a larger group) you can
> > construct representatives of the orbits without storing all sets
> > simultaneously, e.g., by orderly generation[1]. If you are interested I
> > can make available some code which performs this task.
> >
> > Regards,
> > Sven.
> >
> > [1] READ, R.C. Every-one a winner. Ann. Discr. Math., 1978, 2, 107--120.
> >
> > --
> > Sven Reichard
> > School of Mathematics and Statistics
> > University of Western Australia
> >
> >
> >
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> >
>
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