[GiNaC-list] Mixed index simmetry

[mdias at ift.unesp.br]

Hi, 


I am new in Ginac,and have a stupid question. I dont know how to get all
possible permutations of the four index pairs (sigma, l), (mu,m), (nu,n) and
(rho,o). (Its a QCD vertex...) in the expression:


  ex four = color_f(a,b,c)*color_f(a,d,e)*(delta_tensor(l,b)*delta_tensor(m,c)*d
elta_tensor(n,d)*delta_tensor(o,e)*metric_tensor(alpha,sigma)*metric_tensor(beta
,mu)*metric_tensor(nu,alpha.toggle_variance())*metric_tensor(beta.toggle_varianc
e(),rho):

I can make somethink like
four.symmetrize((sigma,l),(mu,m),(nu,n),(rho,o))?

I've looked at the archives and didn t find.
Thanks a lot,


Marco

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