power series in more than one variables
- To: mathgroup at smc.vnet.net
- Subject: [mg55679] power series in more than one variables
- From: "Christoph Lhotka" <lhotka at astro.univie.ac.at>
- Date: Sun, 3 Apr 2005 05:50:48 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Hello !
How can I define a power series in Mathematica with more than more variables
(x,y,z,...), where only terms x^k*y^l*z^m*..., where k+l+m+...=N should be
considered? I havwe tried Series[exp,{x,..},{y,...},...] but this only returns
nested taylor series. My usual approach is to define an artificial
perturbation parameter, say lambda^k+l+m, holding terms of equal powers
together, but this is not satisfying when only dealing with numerical series,
where the coefficients should only be numeric not mixed symbolic (defining it
this way will give you as third argument to SeriesData non numerical entries.
Does anyone have some sugestions?
-- Christoph Lhotka --
University of Vienna
Institute for Astronomy
Tuerkenschanzstr. 17
1180 Vienna, Austria
mail. lhotka at astro.univie.ac.at