**Next message:**Shaowu zhang : "About ApartFF"**Previous message:**Steffen Schwertfeger: "Re: Error in PaVeReduce?"**In reply to:**Steffen Schwertfeger: "Re: Error in PaVeReduce?"**Messages sorted by:**[ date ] [ thread ] [ subject ] [ author ]**Mail actions:**[ respond to this message ] [ mail a new topic ]

Hi,

Am 01.06.2016 um 11:51 schrieb Steffen Schwertfeger:

*> Dear all,
*

*>
*

*> On 01/06/16 11:43, Vladyslav Shtabovenko wrote:
*

*>> The only way to obtain m^2*B0[0, m^2, m^2] that I currently see would
*

*>> be take the D->4 limit via
*

*>>
*

*>> res2/.D->4
*

*>
*

*> which is exactly what I did. Is there a way to properly take the limit?
*

in general, to be able to take the limit correctly you need to know the

coefficient of the 1/Epsilon_UV pole of the PaVe function. Those are

tabulated in the work of Denner et al, c.f. Appendix A of

arXiv:hep-ph/0509141.

Of course, when taking the limit it is always assumed that the PaVe

function is not IR divergent. Which is the case for all A's and B's but

in general not true for C's and D's.

So you could use $LimitTo4=True (which is now safe) to recover the

results that you had in the stable version. One has to keep in mind,

that only some cases for B0, B1, B00 and B11 implemented, so it doesn't

give you a general solution.

Hmm, I guess that for simplifying terms like f(D)*PaVe one could add

a new function that would take the limit for the known cases. Again,

under the assumption that C's and D's are IR finite and f(D) is a

rational function. Let me see how difficult it would be to implement...

Cheers,

Vladyslav

*>
*

*> Kind regards,
*

*> Steffen Schwertfeger
*

*>
*

**Next message:**Shaowu zhang : "About ApartFF"**Previous message:**Steffen Schwertfeger: "Re: Error in PaVeReduce?"**In reply to:**Steffen Schwertfeger: "Re: Error in PaVeReduce?"**Messages sorted by:**[ date ] [ thread ] [ subject ] [ author ]**Mail actions:**[ respond to this message ] [ mail a new topic ]

*
This archive was generated by hypermail 2b29
: 06/23/17-10:40:02 PM Z CEST
*