Univalent Polynomials and Hubbard Trees

Autor: Lazebnik, Kirill, Makarov, Nikolai G., Mukherjee, Sabyasachi
Rok vydání: 2019
Předmět:
Zdroj: Trans. Amer. Math. Soc. 374 (2021), 4839-4893
Druh dokumentu: Working Paper
DOI: 10.1090/tran/8387
Popis: 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).
Databáze: arXiv