Failure of Approximation of Odd Functions by Odd Polynomials
Functional Analysis
2020-07-01 v1 Classical Analysis and ODEs
Complex Variables
Abstract
We construct a Hilbert holomorphic function space on the unit disk such that the polynomials are dense in , but the odd polynomials are not dense in the odd functions in . As a consequence, there exists a function in that lies outside the closed linear span of its Taylor partial sums , so it cannot be approximated by any triangular summability method applied to the . We also show that there exists a function in that lies outside the closed linear span of its radial dilates .
Cite
@article{arxiv.2006.16871,
title = {Failure of Approximation of Odd Functions by Odd Polynomials},
author = {Javad Mashreghi and Pierre-Olivier Parisé and Thomas Ransford},
journal= {arXiv preprint arXiv:2006.16871},
year = {2020}
}
Comments
8 pages. Submitted to Const.Approx. on the 2020/06/23