gap> P:=ClosedSurface(-1);;           
gap> PP:=DirectProduct(P,P);;
gap> SPP:=Suspension(PP);;
gap> A:=CohomologyRing(SPP,2);     
&lt;algebra of dimension 9 over GF(2)&gt;
gap> List(Basis(A),x->Bockstein(A,x));
[ 0*v.1, v.4, v.4+v.6, 0*v.1, v.8, 0*v.1, v.9, 0*v.1, 0*v.1 ]
