gap> G:=AlmostCrystallographicPcpGroup( 4, 50, [ 1, -4, 1, 2 ] );;
gap> R:=ResolutionAlmostCrystalGroup(G,20);
Resolution of length 20 in characteristic 0 for Pcp-group with orders 
[ 4, 0, 0, 0, 0 ] . 

gap> Size(R);
[ 10, 53, 137, 207, 223, 223, 223, 223, 223, 223, 223, 223, 223, 223, 223, 
  223, 223, 223, 223, 223 ]


gap> T:=Kernel(NaturalHomomorphismOnHolonomyGroup(G));;
gap> IsAbelian(T);
false
