+ dim * dirac_gamma5() * dirac_gamma(nu) * dirac_gamma(rho) * dirac_gamma(sig) * dirac_gamma(kap);
e = dirac_trace(e);
e = (e / (dim - 4)).normal();
- result += check_equal(e, 8 * eps0123(nu, rho, sig, kap));
+ result += check_equal(e, 8 * I * eps0123(nu, rho, sig, kap));
// one-loop vacuum polarization in QED
e = dirac_gamma(mu) *