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New York Journal of Mathematics
Volume 32 (2026), 1010-1016

  

Nicolae Mihalache and Francois Vigneron

Factorization of the Misiurewicz-Thurston polynomials

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Published: June 9, 2026.
Keywords: Misiurewicz-Thurston polynomials; Mandelbrot set; Multibrot set; Factorization.
Subject [2020]: 37F10, 26A18, 12D05.

Abstract
This note provides the complete factorization of the Misiurewicz-Thurston polynomial ql,n over C, which plays a central role in the study of the Mandelbrot set and Multibrot sets. The roots can be classified into two categories. First, there are hyperbolic points Hyp(k) for any divisor k of n, which are parameters whose critical orbits are of exact period k. Those are roots of ql,n with multiplicity (d-1)[(l-1)/k]+2. Next are the points Mis(j,k) for 2<=j<=l whose critical orbits are pre-periodic of exact period k with an exact pre-period j. Those are simple roots of ql,n.

Acknowledgements

Research supported by ANR-25-CE40-4532 (Smash).


Author information

Nicolae Mihalache
Universite Paris-Est Creteil
UMR 8050 CNRS
LAMA, F-94010 Creteil, France, and
Universite Gustave Eiffel
LAMA, F-77447 Marne-la-Vallee, France

nicolae.mihalache@u-pec.fr

Francois Vigneron
Universite de Reims Champagne-Ardenne
Laboratoire de Mathématiques de Reims
UMR 9008 CNRS, Moulin de la Housse
BP 1039, F-51687 Reims, France

francois.vigneron@univ-reims.fr