While trying to find a minimal generating set for several permutation
groups I have repeteadly found the following problem:
gap> G := Group((1,4)(2,6)(3,5), > (1,4)(2,5)(3,6), > (1,3,2)(4,5,6), > (1,2,3)(4,5,6)); Group([ (1,4)(2,6)(3,5), (1,4)(2,5)(3,6), (1,3,2)(4,5,6), (1,2,3)(4,5,6) ]) gap> MinimalGeneratingSet(G); Error no method found for operation MinimalGeneratingSet at Error( "no method found for operation ", name ); <function>( <arguments> ) ... gap> EulerianFunction(G,2); Error no method found for operation EulerianFunction with 2 arguments ... gap> Size(G); 36 gap> EulerianFunction(G,2); 216 gap>MinimalGeneratingSet(G); Error no method found for operation InducedPcgsByPcSequenceAndGenerators with \ 3 arguments ...
I suposse this is a bug, (though I am not sure if this is the
correct place to report). I have treated the bugfixes 1 to 4 before
making this test.
Also I don't know if the following code is also a bug or it is simply
gap> G := Group((1,2,3),(1,2));
Group([ (1,2,3), (1,2) ])
gap> F := FreeGroup("a","b");
<free group on the generators [ a, b ]>
Error argument for `ElementsFamily' must have categories `[
"IsFamily" ]' at Error( "argument for `", name, "' must have
categories `", filt, "'" ); ElementsFamily( RelatorsOfFpGroup( f ) )
called from KernelOfMultiplicativeGeneralMapping( i ) called from
<function>( <arguments> ) called from read-eval-loop
Somebody could tell me of a way around this problem, say, how to find
all epimorphism from a free group onto a permutation group.
Esteban Crespi de Valldaura