[GAP Forum] Unexpected behaviour on StructureDescription()

Nilo de Roock ndroock1 at gmail.com
Mon Jan 30 23:07:03 GMT 2006


Hello GAP Forum,

The command

<COMMAND>
StructureDescription(DirectProduct(CyclicGroup(5),SymmetricGroup(4)));
</COMMAND>

generated the following response:

<RESPONSE>
gap> StructureDescription(DirectProduct(CyclicGroup(5),SymmetricGroup(4)));
#I  default `IsGeneratorsOfMagmaWithInverses' method returns `true' for
[ Tuple( [ f1, () ] ) ]
#I  default `IsGeneratorsOfMagmaWithInverses' method returns `true' for
[ Tuple( [ <identity> of ..., (1,2,3,4) ] ) ]
#I  default `IsGeneratorsOfMagmaWithInverses' method returns `true' for
[ Tuple( [ <identity> of ..., (1,2) ] ) ]
Error, <elm> lies not in group defined by <pcgs> called from
ExponentsOfPcElement( pcgs, elm ) called from
IN_LIST_DEFAULT( elm, list ) called from
Enumerator( D ) called from
<compiled or corrupted call value>  called from
func( elm ) called from
...
Entering break read-eval-print loop ...
you can 'quit;' to quit to outer loop, or
you can 'return;' to continue
brk>
</RESPONSE>

I have never seen such a response from GAP. I use GAP mainly for  
"educational algebra" i.e.: only very small, known groups - Is this  
expected GAP behaviour?? If so how should I interpret the message?

Thanks in advance for an answer to my question.

Kind Regards,
nilo de roock



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