English

Polynomial approximation avoiding values in sets II

Classical Analysis and ODEs 2021-08-17 v2 Complex Variables

Abstract

We prove some results on when functions on compact sets KCK \subset \mathbb C can be approximated by polynomials avoiding values in given sets. We also prove some higher dimensional analogues. In particular we prove that a continuous function from a compact set KRnK \subset \mathbb R^n without interior points to Rn\mathbb R^n can be uniformly approximated by a polynomial mapping avoiding values in any given countable set ARnA \subset \mathbb R^n, giving a real nn-dimensional analogue of a recent version of Lavrentiev's theorem of Andersson and Rousu. We also prove the same result for infinite dimensional Banach spaces.

Keywords

Cite

@article{arxiv.2107.14067,
  title  = {Polynomial approximation avoiding values in sets II},
  author = {Johan Andersson},
  journal= {arXiv preprint arXiv:2107.14067},
  year   = {2021}
}

Comments

v2: 12 pages, fixed minor issues and added a result on Banach spaces v1:11 pages; Comments are appreciated