Hello,
thank you both, that seems to do the trick!
Kind regards,
Frédéric
Op 06/11/12 13:16, Muhammad Shah schreef:
Dear Frédéric,
The command OnSet takes two arguments a set and a group g. In the
first case you are taking a set which is orbits[1]:=[1,2]
While in second case it is not a set as (orbits[2]:= [ 3, 4, 7, 8, 10,
12, 5, 6, 9, 11 ] whish is not SSortted so not a set.that is why it
gives error.
you should make it first a set like the following
gap> g:=AllPrimitiveGroups(DegreeOperation,12)[2];
M(12)
gap> h:=Stabilizer(g,[1,2],OnSets);
Group([ (5,9,6,11)(7,12,10,8), (5,10,6,7)(8,9,12,11),
(4,7)(5,8)(6,9)(11,12), (4,8)(5,9)(6,7)(10,11),
(3,4,10,5)(6,7,9,8), (1,2)(4,12)(5,11)(6,10) ])
gap> w:=Random(h);
(3,12)(4,7,10,5,8,6,11,9)
gap> orbits:=Orbits(h,[1..12]);
[ [ 1, 2 ], [ 3, 4, 7, 8, 10, 12, 5, 6, 9, 11 ] ]
gap> OnSets(Set(orbits[2]),w);
[ 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 ]
gap>
I hope this helps
Muhammad Shah
Op 06/11/12 13:05, Burkhard Höfling schreef:
On 2012-11-06, at 12:32 , Frederic Vanhove <fvanh...@cage.ugent.be> wrote:
gap> orbits:=Orbits(h,[1..12]);
[ [ 1, 2 ], [ 3, 4, 7, 8, 10, 12, 5, 6, 9, 11 ] ]
gap> OnSets(orbits[2],w);
OnSets: <set> must be a set (not a list (plain,cyc,nsort,imm))
not in any function
Entering break read-eval-print loop ...
you can 'quit;' to quit to outer loop, or
you can replace <set> via 'return <set>;' to continue
The error message tells you that the second orbit is not a set in the GAP sense
(i.e., a strictly sorted list). As the documentation about Orbits states, the
result contains lists of points, not necessarily sets. To do what you intended,
just convert the list to a set first:
OnSets(Set(orbits[2]),w);
Regards,
Burkhard.
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