SDF[i, j]
denotes the SU(N) Kronecker delta with color indices
i
and j
in the fundamental representation.
SDF[i,j]
is transformed into
SUNFDelta[SUNFIndex[i],SUNFIndex[j]]
by
FeynCalcInternal
.
[a, b] SDF
\delta _{ab}
[a, b] // FCI // StandardForm
SDF
(*SUNFDelta[SUNFIndex[a], SUNFIndex[b]]*)
[a, b] // FCE // StandardForm
SDF
(*SDF[a, b]*)