PairContract2
is like Pair
, but with local contraction properties. It works best with products of Pair
s that are expected to evaluate to a product of scalar products.
PairContract2
symbols are evaluated immediately.PairContract2
symbol containing Momentum
in both slots is immediately converted to a Pair
.4
or D
-dimensionalPairContract2
is an auxiliary function used in higher level FeynCalc functions that require fast contractions between multiple expressions, where Contract
would be too slow.
Overview, Contract, PairContract, PairContract3.
[LorentzIndex[\[Mu]], Momentum[p]] Pair[LorentzIndex[\[Mu]], Momentum[q]]
Pair
% /. Pair -> PairContract2
[LorentzIndex[\[Mu]], Momentum[p + q]] Pair[LorentzIndex[\[Mu]], Momentum[r + s]]
Pair
% /. Pair -> PairContract2