Series expansion

Gentlemen, what's wrong with the following code in GiNaC 0.8.3: int main() { using namespace GiNaC; varidx mu(symbol("mu"),4); symbol eps("eps"); ex g = 1 + eps;; cout << g.series(eps==0,5) << endl; ex h = 1 + eps*dirac_gamma(mu); cout << h.series(eps==0,5) << endl; return 0; } The program crashes when it tries to expand h. Is the series member function actually defined somewhere for an object like dirac_gamma ? Stefan