DiracIndexNames is an option for FCFAConvert, FCCanonicalizeDummyIndices and other functions. It renames the generic dummy Dirac indices to the indices in the supplied list.
Overview, FCFAConvert, FCCanonicalizeDummyIndices, PauliIndexNames, LorentzIndexNames.
DCHN[GA[mu], i, j] DCHN[GA[nu], j, k]
FCCanonicalizeDummyIndices[%]\left(\bar{\gamma }^{\text{mu}}\right){}_{ij} \left(\bar{\gamma }^{\text{nu}}\right){}_{jk}
\left(\bar{\gamma }^{\text{mu}}\right){}_{i\text{FCGV}(\text{di241})} \left(\bar{\gamma }^{\text{nu}}\right){}_{\text{FCGV}(\text{di241})k}
DCHN[GA[mu], i, j] DCHN[GA[nu], j, k]
FCCanonicalizeDummyIndices[%, DiracIndexNames -> {a}]\left(\bar{\gamma }^{\text{mu}}\right){}_{ij} \left(\bar{\gamma }^{\text{nu}}\right){}_{jk}
\left(\bar{\gamma }^{\text{mu}}\right){}_{ia} \left(\bar{\gamma }^{\text{nu}}\right){}_{ak}