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Among Thurston maps (orientation-preserving, postcritically finite branched coverings of the 2-sphere to itself), those that arise as subdivision maps of a finite subdivision rule form a special family. For such maps, we investigate…

Dynamical Systems · Mathematics 2015-08-04 William J. Floyd , Walter R. Parry , Kevin M. Pilgrim

We consider components of Hurwitz moduli space of G-Galois covers and set up a powerful algebraic framework to study the set of corresponding equivalence classes of monodromy maps. Within that we study geometric stabilisation by various…

Algebraic Geometry · Mathematics 2019-05-01 Michael Lönne

For a given group $G$ the orientably regular maps with orientation-preserving automorphism group $G$ are used as the vertices of a graph $\O(G)$, with undirected and directed edges showing the effect of duality and hole operations on these…

Group Theory · Mathematics 2021-11-11 Gábor Gévay , Gareth A. Jones

The orientability problem in real Gromov-Witten theory is one of the fundamental hurdles to enumerating real curves. In this paper, we describe topological conditions on the target manifold which ensure that the uncompactified moduli spaces…

Symplectic Geometry · Mathematics 2013-11-27 Penka Georgieva , Aleksey Zinger

This paper presents a comprehensive analysis of critical point sets in two-layer neural networks. To study such complex entities, we introduce the critical embedding operator and critical reduction operator as our tools. Given a critical…

Machine Learning · Computer Science 2024-05-29 Leyang Zhang , Yaoyu Zhang , Tao Luo

We give a topological interpretation of the core group invariant of a surface embedded in S^4. We show that the group is isomorphic to the free product of the fundamental group of the double branch cover of S^4 with the surface as a…

Geometric Topology · Mathematics 2007-05-23 Jozef H. Przytycki , Witold Rosicki

We consider the homotopical dynamics on compact orientable surfaces of positive genus g. We establish a sufficient and necessary algebraic criterion for homotopy classes with infinitely many periodic points of maps on such surfaces in terms…

Dynamical Systems · Mathematics 2010-06-15 Joerg Kampen

Given two closed orientable surfaces, the Hurwitz existence problem asks whether there exists a branched cover between them having prescribed global degree and local degrees over the branching points. The Riemann-Hurwitz formula gives a…

Geometric Topology · Mathematics 2011-01-18 Ekaterina Pervova , Carlo Petronio

We extend Thurston's combinatorial criterion for postcritically finite rational maps to a class of rational maps with bounded type Siegel disks. The combinatorial characterization of this class of Siegel rational maps plays a special role…

Dynamical Systems · Mathematics 2008-11-20 Gaofei Zhang

A critically finite branched self-cover $f: (S^2, P) \to (S^2, P)$ determines naturally three iterated function systems: one on the pure mapping class group of the sphere marked at $P$, one on the Teichm\"uller space of the sphere marked at…

Dynamical Systems · Mathematics 2025-07-01 Walter Parry , Kevin M. Pilgrim

We study canonical decompositions of postcritically finite branched coverings of the 2-sphere, as defined by K.~Pilgrim. We show that every hyperbolic cycle in the decomposition does not have a Thurston obstruction. It is thus Thurston…

Dynamical Systems · Mathematics 2010-11-18 Sylvain Bonnot , Michael Yampolsky

This is the announcement, and the long summary, of a series of articles on the algorithmic study of Thurston maps. We describe branched coverings of the sphere in terms of group-theoretical objects called bisets, and develop a theory of…

Computational Complexity · Computer Science 2017-06-20 Laurent Bartholdi , Dzmitry Dudko

The goal of this note is to generalize Thurston's Topological Characterization of Rational Functions to the setting when both the covering degree and the set of marked points are infinite. A relevant class of branched coverings are…

Dynamical Systems · Mathematics 2025-07-29 Konstantin Bogdanov

Heteroclinic cycles and networks are structures in dynamical systems composed of invariant sets and connecting heteroclinic orbits, and can be robust in systems with invariant subspaces. The usual method for analysing the stability of…

Dynamical Systems · Mathematics 2026-04-02 David C. Groothuizen Dijkema , Vivien Kirk , Claire M. Postlethwaite

Given an oriented surface of positive genus with finitely many punctures, we classify the finite orbits of the mapping class group action on the moduli space of semisimple complex special linear two dimensional representations of the…

Geometric Topology · Mathematics 2022-06-29 Indranil Biswas , Subhojoy Gupta , Mahan Mj , Junho Peter Whang

Main Theorem: Spaces of r-branch point 3-cycle covers, degree n or Galois of degree n!/2 have one (resp. two) component(s) if r=n-1 (resp. r\ge n). Improves Fried-Serre on deciding when sphere covers with odd-order branching lift to…

Number Theory · Mathematics 2011-01-26 Michael D. Fried

We classify noninvertible, holomorphic selfmaps of the projective plane that preserve an algebraic web. In doing so, we obtain interesting examples of critically finite maps.

Dynamical Systems · Mathematics 2009-07-23 Marius Dabija , Mattias Jonsson

We describe an application of tropical moduli spaces to complex dynamics. A post-critically finite branched covering $\varphi$ of $S^2$ induces a pullback map on the Teichm\"uller space of complex structures of $S^2$; this descends to an…

Dynamical Systems · Mathematics 2025-05-08 Rohini Ramadas

Let $f: S^2 \to S^2$ be a continuous map of degree $d$, $|d|>1$, and let $N_nf$ denote the number of fixed points of $f^n$. We show that if $f$ is a Thurston map with non hyperbolic orbifold, then either the growth rate inequality $\limsup…

Dynamical Systems · Mathematics 2022-11-08 J. Iglesias , A. Portela , A. Rovella , J. Xavier

We give a combinatorial classification for the class of postcritically fixed Newton maps of polynomials as dynamical systems. This lays the foundation for classification results of more general classes of Newton maps. A fundamental…

Dynamical Systems · Mathematics 2019-10-09 Kostiantyn Drach , Yauhen Mikulich , Johannes Rückert , Dierk Schleicher