GSD[p] can be used as input for a D-dimensional p^\mu
\gamma_\mu and is transformed into
DiracGamma[Momentum[p,D],D]
by
FeynCalcInternal
(=FCI
).
GSD[p,q, ...]
is a short form for
GSD[p].GSD[q]
.
Overview, DiracGamma, GA, GAD.
[p] GSD
\gamma \cdot p
[p] // FCI // StandardForm
GSD
(*DiracGamma[Momentum[p, D], D]*)
[p, q, r, s] GSD
(\gamma \cdot p).(\gamma \cdot q).(\gamma \cdot r).(\gamma \cdot s)
[p, q, r, s] // StandardForm
GSD
(*GSD[p] . GSD[q] . GSD[r] . GSD[s]*)
[q] . (GSD[p] + m) . GSD[q] GSD
(\gamma \cdot q).(m+\gamma \cdot p).(\gamma \cdot q)