+static unsigned clifford_check5()
+{
+ // canonicalize_clifford() checks
+
+ unsigned result = 0;
+
+ symbol dim("D");
+ varidx mu(symbol("mu"), dim), nu(symbol("nu"), dim), lam(symbol("lam"), dim);
+ ex e;
+
+ e = dirac_gamma(mu) * dirac_gamma(nu) + dirac_gamma(nu) * dirac_gamma(mu);
+ result += check_equal(canonicalize_clifford(e), 2*dirac_ONE()*lorentz_g(mu, nu));
+
+ e = (dirac_gamma(mu) * dirac_gamma(nu) * dirac_gamma(lam)
+ + dirac_gamma(nu) * dirac_gamma(lam) * dirac_gamma(mu)
+ + dirac_gamma(lam) * dirac_gamma(mu) * dirac_gamma(nu)
+ - dirac_gamma(nu) * dirac_gamma(mu) * dirac_gamma(lam)
+ - dirac_gamma(lam) * dirac_gamma(nu) * dirac_gamma(mu)
+ - dirac_gamma(mu) * dirac_gamma(lam) * dirac_gamma(nu)) / 6
+ + lorentz_g(mu, nu) * dirac_gamma(lam)
+ - lorentz_g(mu, lam) * dirac_gamma(nu)
+ + lorentz_g(nu, lam) * dirac_gamma(mu)
+ - dirac_gamma(mu) * dirac_gamma(nu) * dirac_gamma(lam);
+ result += check_equal(canonicalize_clifford(e), 0);
+
+ return result;
+}
+
+unsigned exam_clifford()