Name: Gang Li Date: 08/03/15-04:26:58 PM Z
Hello, Vladyslav,
I’ve faced with a problem when I want to extract a particular term using
the Mathematica function “Coefficeint”.
Num = TR[(GSD[q] + m).(a + I*b*GA5).(GSD[q + pc] +
m).(a +
I*b*GA5).(GSD[q + pa + pb] +
m).GAD[mu].(GSD[q + pb] + m).GAD[
nu]] // Simplify
tmp = Coefficient[Num, a*a] // Simplify
-——————————————–
Coefficient[tmp, MTD[mu, nu]] = 0 (does not work!)
_____________________________________________
However,
Coefficient[tmp, Pair[LorentzIndex[mu, D],
LorentzIndex[nu, D]]]
works well.
Why does FeynCalc contain different input forms of the same expression?