A note on formal power series
Commentationes Mathematicae Universitatis Carolinae, Tome 51 (2010) no. 4, pp. 595-604
Cet article a éte moissonné depuis la source Czech Digital Mathematics Library
In this note we investigate a relationship between the boundary behavior of power series and the composition of formal power series. In particular, we prove that the composition domain of a formal power series $g$ is convex and balanced which implies that the subset $\overline{\mathbb X}_g $ consisting of formal power series which can be composed by a formal power series $g$ possesses such properties. We also provide a necessary and sufficient condition for the superposition operator $T_g$ to map $\overline{\mathbb X}_g$ into itself or to map ${\mathbb X}_g$ into itself, respectively.
In this note we investigate a relationship between the boundary behavior of power series and the composition of formal power series. In particular, we prove that the composition domain of a formal power series $g$ is convex and balanced which implies that the subset $\overline{\mathbb X}_g $ consisting of formal power series which can be composed by a formal power series $g$ possesses such properties. We also provide a necessary and sufficient condition for the superposition operator $T_g$ to map $\overline{\mathbb X}_g$ into itself or to map ${\mathbb X}_g$ into itself, respectively.
Classification :
13F25, 40A30, 52A05
Keywords: composition; end behavior of convergence of power series; convex and balanced set; formal power series
Keywords: composition; end behavior of convergence of power series; convex and balanced set; formal power series
@article{CMUC_2010_51_4_a4,
author = {Gan, Xiao-Xiong and Bugajewski, Dariusz},
title = {A note on formal power series},
journal = {Commentationes Mathematicae Universitatis Carolinae},
pages = {595--604},
year = {2010},
volume = {51},
number = {4},
mrnumber = {2858263},
zbl = {1224.13025},
language = {en},
url = {http://geodesic.mathdoc.fr/item/CMUC_2010_51_4_a4/}
}
Gan, Xiao-Xiong; Bugajewski, Dariusz. A note on formal power series. Commentationes Mathematicae Universitatis Carolinae, Tome 51 (2010) no. 4, pp. 595-604. http://geodesic.mathdoc.fr/item/CMUC_2010_51_4_a4/