Thanks, William! I guess so far it only works over Q?
--Matt On Dec 7, 7:43 pm, William Stein <wst...@gmail.com> wrote: > 2009/12/7 Matt Bainbridge <bainbridge.m...@gmail.com>: > > > Hi there, > > > Does anyone know if Sage has a function for computing the composition > > inverse of a power series (not the reciprocal)? > > Yep, we have that: > > sage: R.<x> = QQ[[]] > sage: f = 1/(1-x) - 1; f > x + x^2 + x^3 + x^4 + x^5 + x^6 + x^7 + x^8 + x^9 + x^10 + x^11 + x^12 > + x^13 + x^14 + x^15 + x^16 + x^17 + x^18 + x^19 + O(x^20) > sage: g = f.reversion(); g > x - x^2 + x^3 - x^4 + x^5 - x^6 + x^7 - x^8 + x^9 - x^10 + x^11 - x^12 > + x^13 - x^14 + x^15 - x^16 + x^17 - x^18 + x^19 + O(x^20) > sage: f(g) > x + O(x^20) > > > --Matt > > > P.S. Just started using sage and finding it very useful. Thanks for > > developing it. > > > -- > > To post to this group, send email to sage-support@googlegroups.com > > To unsubscribe from this group, send email to > > sage-support-unsubscr...@googlegroups.com > > For more options, visit this group > > athttp://groups.google.com/group/sage-support > > URL:http://www.sagemath.org > > -- > William Stein > Associate Professor of Mathematics > University of Washingtonhttp://wstein.org -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
