Re: periodic generating function

[Kevin Ryde <user42_kevin@yahoo.com.au>]

Karim Belabas <Karim.Belabas@math.u-bordeaux.fr> writes:
>
>    ( or guess via bestappr( log(z1/z2)/2*I*Pi ) )

Hmm.  Sounds promising, if only to keep a lid on the size of
intermediate terms if I'm actually not periodic.

>    I see no way to rule out arbitrarily large p without further
>    information.

Oh, could be an idea there.  My poly is from guessing on a certain
number of original values so maybe the period is at most that many.

> (I guess that your input is exact and that you can check whether any
> tentative value is actually correct.)

Yes.  Values only rational complex and quads persumably restrict the
sort of polys which would occur too, but in what way might be tricky.