FeynCalc manual (development version)

PauliSigmaCombine

PauliSigmaCombine[exp] is (nearly) the inverse operation to PauliSigmaExpand.

See also

Overview, PauliSigmaExpand.

Examples

SIS[p] + SIS[q] 
 
PauliSigmaCombine[%]

σˉp+σˉq\bar{\sigma }\cdot \overline{p}+\bar{\sigma }\cdot \overline{q}

σˉ(p+q)\bar{\sigma }\cdot \left(\overline{p}+\overline{q}\right)

PauliXi[-I] . (SIS[p1 + p2] + SIS[q]) . PauliEta[I] 
 
PauliSigmaCombine[%]

ξ.(σˉ(p1+p2)+σˉq).η\xi ^{\dagger }.\left(\bar{\sigma }\cdot \left(\overline{\text{p1}}+\overline{\text{p2}}\right)+\bar{\sigma }\cdot \overline{q}\right).\eta

ξ.(σˉ(p1+p2+q)).η\xi ^{\dagger }.\left(\bar{\sigma }\cdot \left(\overline{\text{p1}}+\overline{\text{p2}}+\overline{q}\right)\right).\eta