Name: FengF (email_not_shown)
Date: 04/07/06-06:48:20 AM Z


Hi , Sir

I have a problem with the Tr and Calc Command

The example is :

Lepton=FV[k1,mu]FV[k2,nu]+FV[k2,mu]VF[k1,nu]-SP[k1,k2]MT[mu,nu]

Quark=FV[p3,alhpa]FV[k,beta]+FV[k,alpha]VF[p3,beta]-SP[k,p3]MT[alpha,beta]

AA=GA[mu].(GS[p1+p3-k]+m).GS[alpha].(GS[p1]+m).GS[5].GS[S].GA[nu].(GS[k+p2-p3]+m).GA[beta].(GS[p2]-m)

Calc[Quark Lepton Tr[AA]]

and

Calc[Tr[Quark Lepton Calc[AA]]]

give different results

tr=TR[Calc[#]]&;

Calc[Quark Lepton Tr[AA]]

give the same result as

Calc[Tr[Quark Lepton Calc[AA]]]

and

Calc[Quark Lepton Tr[Calc[AA]]]

So is it nessissery to use the Calc before Tr ?

Thanks



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