theorem
  for V being RealLinearSpace, v being VECTOR of V holds Sum<* v,v,v *> = 3 * v
proof
  let V be RealLinearSpace, v be VECTOR of V;
  thus Sum<* v,v,v *> = Sum<* v,v *> + v by Th65
    .= 2 * v + v by Th60
    .= 2 * v + 1 * v by Def8
    .= (2 + 1) * v by Def6
    .= 3 * v;
end;
