Problem with Levi-Civita

[gekatsia]

Hi,
I am using Feyncalc 9.3.1 (stable version) in Mathematica 13.0 in a windows laptop.
I am trying to simplify expressions that contain gamma matrices contracted with the Levi -Civita tensor, but Mathematica does not cancel terms such as the one given below (a,b are dummy indices)

(DiracMatrix[a] Eps[m, n, r, a] - DiracMatrix[b] Eps[m, n, r, b]) // Contract // DiracReduce
I have used Feyncalc in the past, and older versions could 'see' that the above expression evaluates to zero.
Now I have tried a couple of things, but nothing seems to work.
I would appreciate any suggestions.
Thank you.

[vsht]

Hi,

• DiracMatrix is deprecated, please use GA instead.
• Eps is an internal symbol and the notation Eps[a,b,c,d] is not supported anymore. The correct shortcut is called LC.

To simplify such expressions one needs to canonicalize the dummy indices:

(GA[a] LC[m, n, r, a] - GA[b] LC[m, n, r, b]) // FCCanonicalizeDummyIndices

[gekatsia]

Thank you very much!!