CoCalc -- EulerChar.gi

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GAP 4.8.9 installation with standard packages -- copy to your CoCalc project to get it

Project: cocalc-sagemath-dev-slelievre

Path: gap4r8 / pkg / Hap1.12 / lib / TorsionSubcomplexes / EulerChar.gi

Views: ⁴¹⁸³⁸⁴

InstallGlobalFunction(EquivariantEulerCharacteristic,
function(C)

local N,i,j,t;

N:=0;
while C!.dimension(N)>0 do
    N:=N+1;
od;
N:=N-1;
t:=0;
for i in [0..N] do
    for j in [1..C!.dimension(i)] do
        t:=t+(-1)^i*(1/Size(C!.stabilizer(i,j)));
    od;
od;

return t;
end);