"Source: Text/Algebra/AlgClff.text";
"Line: 397";
"Date: Thu Sep 25 14:47:46 2025";
"Main: Fri Sep 26 14:29:19 2025";
// original file: Text/Algebra/AlgClff.text, line: 397
// Example: H97E7 ()
print "Example: H97E7";
ei := GetEchoInput();
SetEchoInput(true);
F := GF(3);
Q := StandardQuadraticForm(6,F);
C,V,f := CliffordAlgebra(Q);
WittIndex(V);
IsSimple(C);
assert $1;
#Centre(C);
E,h := EvenSubalgebra(C);
IsSimple(E);
#MinimalIdeals(E);
Z := Centre(E); Z;
#{ z : z in Z | IsUnit(z) };
exists(z){ z : z in Z | z^2 eq One(E) and 
  forall{ v : v in V | f(v)*h(z) eq - h(z)*f(v) } };
assert $1;
E1 := ideal< E | 1-z >;
IsSimple(E1);
assert $1;
E2 := ideal< E | 1+z >;
IsSimple(E2);
assert $1;
SetEchoInput(ei);
