[GAP Forum] Finding a representative which moves fewest points
Warwick Harvey
wh at icparc.ic.ac.uk
Thu Apr 1 00:37:29 BST 2004
Dear GAP Forum,
I am a relative novice when it comes to GAP and group theory, so please
excuse me if I've missed something obvious.
What I would like is a function like RepresentativeAction which returns a
representative that moves as few points as possible. Taking the example
from the manual:
gap> g:=Group((1,3,2),(2,4,3));;
gap> RepresentativeAction(g,1,3);
(1,3)(2,4)
I would like instead the element (1,3,2), since this only moves 3 points
rather than 4. I tried constructing cosets of the stabilizer of 1 and using
RepresentativeSmallest on the appropriate coset, but of course the notion of
smallest there is not what I want.
I have an algorithm in mind that I could use to construct a representative
of the form I desire, but don't want to re-invent the wheel if there's
already an easy way to do it.
Thanks for any tips.
Cheers,
Warwick
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