"Source: Text/Algebra/AlgNAss.text";
"Line: 191";
"Date: Thu Sep 25 14:47:46 2025";
"Main: Fri Sep 26 14:29:19 2025";
// original file: Text/Algebra/AlgNAss.text, line: 191
// Example: H98E4 ()
print "Example: H98E4";
ei := GetEchoInput();
SetEchoInput(true);
M := MatrixAlgebra(GF(3), 4);
f := ConwayPolynomial(3, 2);
C := CompanionMatrix(f);
I := IdentityMatrix(GF(3), 2);
A := sub< M | [InsertBlock(M!0, X, i, j) : 
    X in [I, C], i in [1, 3], j in [1, 3]] >;
T := CommutatorTensor(A);
T;
GL2 := HeisenbergAlgebra(T);
GL2;
SL2 := GL2/Center(GL2);
SL2;
Center(SL2);
Centroid(SL2);
SetEchoInput(ei);
