Quelle  12.1a.txt

gap> Homology(W,0);Homology(W,1);Homology(W,2);Homology(W,3);
[ 0 ]
[ 16 ]
[  ]
[ 0 ]

gap> F:=FundamentalGroup(W);;
gap> L:=LowIndexSubgroupsFpGroup(F,10);;
gap> List(L,AbelianInvariants);
[ [ 16 ], [ 3, 8 ], [ 3, 4 ], [ 2, 3 ], [ 16, 43 ], [ 8, 43, 43 ] ]