e = dirac_gamma(mu, 0) * dirac_gamma(mu.toggle_variance(), 1) * dirac_gamma(nu, 0) * dirac_gamma(nu.toggle_variance(), 1);
result += check_equal_simplify(dirac_trace(e, 0), 4 * dim * dirac_ONE(1));
result += check_equal_simplify(dirac_trace(e, 1), 4 * dim * dirac_ONE(0));
e = dirac_gamma(mu, 0) * dirac_gamma(mu.toggle_variance(), 1) * dirac_gamma(nu, 0) * dirac_gamma(nu.toggle_variance(), 1);
result += check_equal_simplify(dirac_trace(e, 0), 4 * dim * dirac_ONE(1));
result += check_equal_simplify(dirac_trace(e, 1), 4 * dim * dirac_ONE(0));