Name: rolf_at_HIDDEN-E-MAIL Date: 03/27/04-04:07:50 PM Z


Hi,
I do get the antisymmetric part (with 5.0beta1):

In[21]:= Tr[1/32 GA[m] . (1 - GA[5]) . GS[k] . (1 + GA[5]) . GA[n] . (1 - GA[5]) . GS[p] .(1 + GA[5])]//Expand

Out[21]= eps[m, n, k, p] - g[m, n] k.p + k[n] p[m] + k[m] p[n]

Notice that the sign is kind of a convention:

In[22]:= Tr[GA[m,n,x,y,5]]

Out[22]= -4 eps[m, n, x, y]

There is an option LeviCivitaSign which you have to set for
both DiracTrace and TR and then you can get a different sign:

In[36]:= SetOptions[DiracTrace, LeviCivitaSign->-I];

In[37]:= SetOptions[TR, LeviCivitaSign->-I];

In[38]:= Tr[GA[m,n,x,y,5]]

Out[38]= 4 eps[m, n, x, y]

Regards,

Rolf Mertig