"Source: Text/Commut/RngInvar.text";
"Line: 301";
"Date: Thu Sep 25 14:47:46 2025";
"Main: Fri Sep 26 14:29:19 2025";
// original file: Text/Commut/RngInvar.text, line: 301
// Example: H120E1 ()
print "Example: H120E1";
ei := GetEchoInput();
SetEchoInput(true);
K := QuadraticField(2);
Aq := [ x / K.1 : x in [1, 1, -1, 1]];
G := MatrixGroup<2, K | Aq>;
P<x, y> := PolynomialRing(K, 2);
f := x^2 + x * y + y^2;
g := f^G.1;
g;
f^G;
SetEchoInput(ei);
