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InstallMethod(CohomologyRing,[IsCObject,IsPosInt],
function(C,n)
local L,R;
ProjectiveResolution(C,n);
if not IsBound(C!.A) or Dimension(C!.A)<Sum(C!.B{[1..n+1]}) then
MakeMultiplicationTable(C,n);
C!.A:=AlgebraByStructureConstants(C!.K,C!.T);
L:=GeneratorsOfAlgebra(C!.A);
R:=rec(
source:=Integers,
hom_components:=function(m)
local r,s;
if m<0 or m>n then
return Subspace(C!.A,[Zero(C!.A)]);fi;
r:=Sum([1..m], x->C!.B[x]);
s:=Sum([1..m+1],x->C!.B[x]);
return Subspace(C!.A,L{[r+1..s]});end,
min_degree:=0,
max_degree:=Size(C!.B)-1
);
C!.A!.AssociatedCohomologyObject:=C;
SetGrading(C!.A,R);
fi;
return C!.A;
end
);
InstallOtherMethod(CohomologyRing,
[IsGroup,IsPosInt],
function(G,n)
local C;
if not IsFinite(G) or not IsPGroup(G)
then TryNextMethod();
fi;
C:=CohomologyObject(G);
CohomologyRing(C,n);
return C!.A;
end
);
[ Dauer der Verarbeitung: 0.34 Sekunden
(vorverarbeitet)
]
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