SUNFIndex[a]
is an SU(N) index in the fundamental
representation. If the argument is an integer, SUNFIndex[a]
turns into ExplicitSUNFIndex[a]
.
[i] SUNFIndex
i
[i] // StandardForm
SUNFIndex
(*SUNFIndex[i]*)
[2] SUNFIndex
2
[2] // StandardForm
SUNFIndex
(*ExplicitSUNFIndex[2]*)
[i, j] // FCI // StandardForm
SUNFDelta
(*SUNFDelta[SUNFIndex[i], SUNFIndex[j]]*)