"Source: Text/Commut/RngInvar.text";
"Line: 2221";
"Date: Thu Sep 25 14:47:46 2025";
"Main: Fri Sep 26 14:29:19 2025";
// original file: Text/Commut/RngInvar.text, line: 2221
// Example: H120E19 ()
print "Example: H120E19";
ei := GetEchoInput();
SetEchoInput(true);
n:=3;
P<[x]>:=PolynomialRing(RationalField(), n*4, "grevlex");
L_A := [MatrixRing(P,2)!x[i..i+3]:i in [1..n*4 by 4]];
IG := ideal<P|[Determinant(A)-1:A in L_A]>;
IG;

M:=L_A[1];
for i:=2 to n do
    M:=TensorProduct(M,L_A[i]);
end for;
M;
IR:=InvariantRing(IG, M: Reductive);
time FundamentalInvariants(IR);
time DerksenIdeal(IR);
time HilbertIdeal(IR);
SetEchoInput(ei);
