[GiNaC-list] series((x+x^2)^2,x,0) is broken

[Vladimir V. Kisil]

>>>>> On Sat, 24 Jun 2023 20:17:27 +0200, "Richard B. Kreckel" <kreckel at in.terlu.de> said:

    RK> Dear Vitaly, Thanks for your excellent treatise on the subject!

    RK> On 6/24/23 19:28, Vitaly Magerya wrote:
    >> This is why 1/(Order(x^n)) is not Order(x^-n), it can be
    >> Order(x^(-n-1)), or lower.

    RK> Okay.  What would be the correct code for Order_power(x,e),
    RK> then?  What about non-integers?

    I may be missing something, but I do not believe there is a
  meaningful connection between orders of f(x) and 1/f(x) as big-O. For
  example, Order(x^k*sin(1/x))=Order(k) at x=0  but
  Order(x^{-1}/sin(1/x)) is not finite.
-- 
Vladimir V. Kisil                 http://www1.maths.leeds.ac.uk/~kisilv/
  Book:      Geometry of Mobius Maps       https://doi.org/10.1142/p835
  Soft:      Geometry of cycles         http://moebinv.sourceforge.net/
  Jupyter notebooks:        https://github.com/vvkisil?tab=repositories