[GAP Forum] Error given by StructureDescription function

[krishna mohan]

Hi...

I run the following lines of code.

gap> A:=[[0,1,0],[0,0,1],[1,0,0]]; B:=[[0,0,1],[0,1,0],[-1,0,0]]; 
C:=[[E(4),0,0],[0,E(4)^(-1),0],[0,0,1]];
gap> g2:=GroupWithGenerators([A,B,C]);       
<matrix group with 3 generators>
gap> StructureDescription(g2);
recursion depth trap (5000)
 at
if func( elm )  then
    return true;
fi;
 called from
ForAny( mat, function ( r )
      return not IsPlistRep( r );
  end ) called from
ac( i, g ) called from
func( elm ) called from
List( set, function ( i )
      return ac( i, g );
  end ) called from
act( b, elm ) called from
...
Entering break read-eval-print loop ...
you can 'quit;' to quit to outer loop, or
you may 'return;' to continue
brk> 


But I can identify the group by doing:
gap> IdGroup(g2);                                               
[ 96, 64 ]

I can generate the same group using a different set of generators. Then, 
StructureDescription works fine. 

Why is it that there is a problem with this set of generators? How can I bypass 
this problem?

Krishna

Krishnamohan P
Graduate Student
IUCAA
Pune 
India