def _gamma_trace1(*a):
    gctr = 4
    g = LorentzIndex.metric
    if (not a):
        return gctr
    n = len(a)
    if ((n % 2) == 1):
        return S.Zero
    if (n == 2):
        ind0 = a[0].get_indices()[0]
        ind1 = a[1].get_indices()[0]
        return (gctr * g(ind0, ind1))
    if (n == 4):
        ind0 = a[0].get_indices()[0]
        ind1 = a[1].get_indices()[0]
        ind2 = a[2].get_indices()[0]
        ind3 = a[3].get_indices()[0]
        return (gctr * (((g(ind0, ind1) * g(ind2, ind3)) - (g(ind0, ind2) * g(ind1, ind3))) + (g(ind0, ind3) * g(ind1, ind2))))
def _gamma_trace1(*a):
    gctr = 4
    g = LorentzIndex.metric
    if (not a):
        return gctr
    n = len(a)
    if ((n % 2) == 1):
        return S.Zero
    if (n == 2):
        ind0 = a[0].get_indices()[0]
        ind1 = a[1].get_indices()[0]
        return (gctr * g(ind0, ind1))
    if (n == 4):
        ind0 = a[0].get_indices()[0]
        ind1 = a[1].get_indices()[0]
        ind2 = a[2].get_indices()[0]
        ind3 = a[3].get_indices()[0]
        return (gctr * (((g(ind0, ind1) * g(ind2, ind3)) - (g(ind0, ind2) * g(ind1, ind3))) + (g(ind0, ind3) * g(ind1, ind2))))