FeynCalc manual (development version)

KDE

KDE[i, j] is the Kronecker delta in D-4 dimensions.

See also

Overview, CartesianPair, KD, KDD.

Examples

KDE[i, j]

\hat{\delta }^{ij}

Contract[KDE[i, j] KDE[i, j]]

D-4

Contract[KDE[i, j] KD[i, j]]

0

Contract[KDE[i, j] KDD[i, j]]

D-4

KDE[i, j] // StandardForm

(*KDE[i, j]*)
FCI[KDE[i, j]] // StandardForm

(*CartesianPair[CartesianIndex[i, -4 + D], CartesianIndex[j, -4 + D]]*)
FCE[FCI[KDE[i, j]]] // StandardForm

(*KDE[i, j]*)