DiracChainCombine
DiracChainCombine[exp]
is (nearly) the inverse operation to DiracChainExpand
.
See also
Overview, DiracChain, DCHN, DiracIndex, DiracIndexDelta, DIDelta, DiracChainJoin, DiracChainExpand, DiracChainFactor.
Examples
(DCHN[GSD[q], Dir3, Dir4] FAD[{k, me}])/(2 SPD[q, q]) + 1/(2 SPD[q, q]) FAD[k,
{k - q, me}] (-2 DCHN[GSD[q], Dir3, Dir4] SPD[q, q] + 2 DCHN[1, Dir3, Dir4] me SPD[q, q] +
DCHN[GSD[q], Dir3, Dir4] (-me^2 + SPD[q, q]))
DiracChainCombine[%]
2q2k2.((k−q)2−me2)(q2−me2)(γ⋅q)Dir3Dir4+2meq2(1)Dir3Dir4−2q2(γ⋅q)Dir3Dir4+2q2(k2−me2)(γ⋅q)Dir3Dir4
2q2k2.((k−q)2−me2)((q2−me2)γ⋅q+2meq2−2q2γ⋅q)Dir3Dir4+2q2(k2−me2)(γ⋅q)Dir3Dir4