Sendov's Conjecture: A note on a paper of Dégot
Abstract
Sendov's conjecture states that if all the zeroes of a complex polynomial $P(z)$ of degree at least two lie in the unit disk, then within a unit distance of each zero lies a critical point of $P(z)$. In a paper that appeared in 2014, Dégot proved that, for each $a\in (0,1)$, there exists an integer $N$ such that for any polynomial $P(z)$ with degree greater than $N$, if $P(a) = 0$ and all zeroes lie inside the unit disk, the disk $|z-a|\leq 1$ contains a critical point of $P(z)$. Based on this result, we derive an explicit formula $\mathcal{N}(a)$ for each $a \in (0,1)$ and, consequently obtain a uniform bound $N$ for all $a\in [\alpha , \beta]$ where $0<\alpha < \beta < 1$. This (partially) addresses the questions posed in Dégot's paper.
- Publication:
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arXiv e-prints
- Pub Date:
- April 2018
- DOI:
- arXiv:
- arXiv:1804.09953
- Bibcode:
- 2018arXiv180409953C
- Keywords:
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- Mathematics - Complex Variables
- E-Print:
- 19 pages