English

Random power series near the endpoint of the convergence interval

Classical Analysis and ODEs 2017-09-13 v1

Abstract

In this paper, we are going to consider power series n=1anxn, \sum_{n=1}^{\infty} a_nx^n, where the coefficients ana_n are chosen independently at random from a finite set with uniform distribution. We prove that if the expected value of the coefficients is positive (resp. negative), then limx1n=1anxn=(resp. limx1n=1anxn=) \lim_{x\to 1-}\sum_{n=1}^{\infty} a_nx^n=\infty\qquad (\text{resp. }\lim_{x\to 1-}\sum_{n=1}^{\infty} a_nx^n=-\infty) with probability 11. Also, if the expected value of the coefficients is 00, then lim supx1n=1anxn=,lim infx1n=1anxn= \limsup_{x\to 1-}\sum_{n=1}^{\infty} a_nx^n=\infty,\qquad \liminf_{x\to 1-}\sum_{n=1}^{\infty} a_nx^n=-\infty with probability 11. We investigate the analogous question in terms of Baire categories.

Keywords

Cite

@article{arxiv.1709.03705,
  title  = {Random power series near the endpoint of the convergence interval},
  author = {Balázs Maga and Péter Maga},
  journal= {arXiv preprint arXiv:1709.03705},
  year   = {2017}
}