DiracGammaExpand[exp] expands all DiracGamma[Momentum[a+b+..]] in exp into (DiracGamma[Momentum[a]] + DiracGamma[Momentum[b]] + ...).
See also: DiracGamma, DiracGammaCombine, DiracMatrix, DiracSimplify, DiracSlash, DiracTrick.
Momentum is the head of p-q, i.e., it is treated as one four-momentum.
With DiracGammaExpand the Momentum[p-q] gets expanded.
The inverse operation is DiracGammaCombine.
In order to do non-commutative expansion use DiracSimplify.
|The FeynCalc Book||DiracGammaCombine||DiracGammaT|