Name: George Katsianis Date: 09/30/19-12:06:11 PM Z


Hi,

I am new to Feyncalc and I am facing the following problem. I am doing the following:
I set `q3=-q2-q1;`

Then I write

    Pair[LorentzIndex[k],
    Momentum[q3]] - (-Pair[LorentzIndex[k], Momentum[q2]] -
     Pair[LorentzIndex[k], Momentum[q1]])) // DiracReduce

and I get

    FV[q1, k] + FV[-q1 - q2, k] + FV[q2, k]

Now if I multiply the above with a gamma matrix, let’s say for instance GA5 i.e.

     (Pair[LorentzIndex[k],
    Momentum[q3]] - (-Pair[LorentzIndex[k], Momentum[q2]] -
     Pair[LorentzIndex[k], Momentum[q1]])))GA5 // DiracReduce
I get zero as I am supposed to find.

Is this is bug? I cannot make the first expression equal to zero,but when I multiply it with something else then mathematica shows that it is indeed zero. Similar things happen with more complicated expressions.
Thank you