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^ Subject:

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

not implemented:

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 ]>

gap> GQuotients(F,G);

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.

Thank you.

Esteban Crespi de Valldaura

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