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arXiv · 1908.05813

Univalent Polynomials and Hubbard Trees

Kirill Lazebnik·Nikolai G. Makarov·Sabyasachi Mukherjee
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Abstract

We study rational functions $f$ of degree $d+1$ such that $f$ is univalent in the exterior unit disc, and the image of the unit circle under $f$ has the maximal number of cusps ($d+1$) and double points $(d-2)$. We introduce a bi-angled tree associated to any such $f$. It is proven that any bi-angled tree is realizable by such an $f$, and moreover, $f$ is essentially uniquely determined by its associated bi-angled tree. This combinatorial classification is used to show that such $f$ are in natural 1:1 correspondence with anti-holomorphic polynomials of degree $d$ with $d-1$ distinct, fixed critical points (classified by their Hubbard trees).

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Kirill Lazebnik, Nikolai G. Makarov, Sabyasachi Mukherjee. 2019-08-16. Univalent Polynomials and Hubbard Trees. https://doi.org/10.1090/tran/8387

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