English

On approximate Gauss-Lucas theorems

Complex Variables 2017-06-20 v1

Abstract

The Gauss--Lucas theorem states that any convex set KCK\subset\mathbb{C} which contains all nn zeros of a degree nn polynomial pC[z]p\in\mathbb{C}[z] must also contain all n1n-1 critical points of pp. In this paper we explore the following question: for which choices of positive integers nn and kk, and positive real number ϵ\epsilon, will it follow that for every degree nn polynomial pp with at least kk zeros lying in KK, pp will have at least k1k-1 critical points lying in the ϵ\epsilon-neighborhood of KK. We supply an inequality relating nn, kk, and ϵ\epsilon which, when satisfied, guarantees a positive answer to the above question.

Keywords

Cite

@article{arxiv.1706.05410,
  title  = {On approximate Gauss-Lucas theorems},
  author = {Trevor Richards},
  journal= {arXiv preprint arXiv:1706.05410},
  year   = {2017}
}

Comments

9 pages

R2 v1 2026-06-22T20:21:19.787Z