Name: Vladyslav Shtabovenko (email_not_shown)
Date: 06/13/17-08:31:10 PM Z


Hi Ana,

for PaVe functions, FeynCalc uses the convention of A. Denner, c.f.

<https://github.com/FeynCalc/feyncalc/wiki/Literature#decomposition-of-tensor-and-scalar-integrals>

The momenta routings are well illustrated in the LoopTools manual

<http://www.feynarts.de/looptools/LT28Guide.pdf>

This is different from the original convention of Passarino and Veltman
(1979) which I believe you are referring to. Hence, in FeynCalc the
indices of 3-point coefficient function can takes values only between 0
and 2.

Cheers,
Vladyslav

Am 13.06.2017 um 17:04 schrieb Ana Penuelas:
> Dear FeynCalc users,
>
> First thanks for contributing with such an useful package. I've found a possible bug in PaVeReduce. If I try to apply PaVeReduce to some PaVe functions I get the following error:
>
> PaVeReduce[PaVe[2, 4, {a, b, c}, {d, e, f}]]
>
> Part::partw: Part 4 of ((4 c)/(-a^2+2 a b-b^2+2 a c+2 b c-c^2) (2 (-a+b-c))/(-a^2+2 a b-b^2+2 a c+2 b c-c^2)
> (2 (-a+b-c))/(-a^2+2 a b-b^2+2 a c+2 b c-c^2) (4 a)/(-a^2+2 a b-b^2+2 a c+2 b c-c^2)
>
> ) does not exist.
>
> Part::partw: Part 4 of ((4 c)/(-a^2+2 a b-b^2+2 a c+2 b c-c^2) (2 (-a+b-c))/(-a^2+2 a b-b^2+2 a c+2 b c-c^2)
> (2 (-a+b-c))/(-a^2+2 a b-b^2+2 a c+2 b c-c^2) (4 a)/(-a^2+2 a b-b^2+2 a c+2 b c-c^2)
>
> ) does not exist.
>
> Part::partw: Part 4 of ((4 c)/FeynCalc`SharedTools`Private`plus(-a^2,2 a b,-b^2,2 a c,2 b c,-c^2) (2 FeynCalc`SharedTools`Private`plus(-a,b,-c))/FeynCalc`SharedTools`Private`plus(-a^2,2 a b,-b^2,2 a c,2 b c,-c^2)
> (2 FeynCalc`SharedTools`Private`plus(-a,b,-c))/FeynCalc`SharedTools`Private`plus(-a^2,2 a b,-b^2,2 a c,2 b c,-c^2) (4 a)/(<<33>>(-a^2,<<4>>,-c^2))
>
> ) does not exist.
>
> General::stop: Further output of Part::partw will be suppressed during this calculation.
>
> Thaks for your help,
>
> Ana PeƱuelas
>



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