I am calculating products like
in mathematica. In the given relations eta's are four vectors, $\gamma$'s are the Dirac matrices, $\sigma^{\mu\nu}$ is the anticommutation of the gamma matrices and some constants are involved.
I have written a mathematica code component be component which is correct and the results are fine.
But the component wise code is too long and cumbersome.
How to write a compact code for such type of products.
Also I do not know how to write the code for
$\eta_\mu \eta_\nu (p^\mu k^\nu - k^\mu p^\nu)$ where p and k are four vectors. Any help will be appreciated. Thank you. Some one might help me in tagging the correct groups.