FeynCalc manual (development version)

DiracGammaCombine

DiracGammaCombine[exp] is (nearly) the inverse operation to DiracGammaExpand.

See also

Overview, DiracGamma, DiracGammaExpand, DiracSimplify, DiracTrick.

Examples

GS[p] + GS[q] 
 
ex = DiracGammaCombine[%]

γˉp+γˉq\bar{\gamma }\cdot \overline{p}+\bar{\gamma }\cdot \overline{q}

γˉ(p+q)\bar{\gamma }\cdot \left(\overline{p}+\overline{q}\right)

ex // StandardForm

(*DiracGamma[Momentum[p + q]]*)
2 GSD[p] - 3 GSD[q] 
 
ex = DiracGammaCombine[%]

2γp3γq2 \gamma \cdot p-3 \gamma \cdot q

γ(2p3q)\gamma \cdot (2 p-3 q)

ex // StandardForm

(*DiracGamma[Momentum[2 p - 3 q, D], D]*)
DiracGammaCombine[2 GSD[p] - 3 GSD[q]] 
 
DiracGammaExpand[%]

γ(2p3q)\gamma \cdot (2 p-3 q)

2γp3γq2 \gamma \cdot p-3 \gamma \cdot q