Welcome to the preprint server of the Institute for Mathematical Sciences at Stony Brook University.

The IMS preprints are also available from the mathematics section of the arXiv e-print server, which offers them in several additional formats. To find the IMS preprints at the arXiv, search for Stony Brook IMS in the report name.

**PREPRINTS IN THIS SERIES, IN PDF FORMAT.**

* Starred papers have appeared in the journal cited.

*Renormalization of Unicritical Diffeomorphisms of the Disk*

We introduce a class of infinitely renormalizable, unicritical diffeomorphisms of the disk (with a non-degenerate "critical point"). In this class of dynamical systems, we show that under renormalization, maps eventually become Hénon-like, and then converge super-exponentially fast to the space of one-dimensional unimodal maps. We also completely characterize the local geometry of every stable and… ▽ More

*On quasiconformal non-equivalence of gasket Julia sets and limit sets*

This paper studies quasiconformal non-equivalence of Julia sets and limit sets. We proved that any Julia set is quasiconformally different from the Apollonian gasket. We also proved that any Julia set of a quadratic rational map is quasiconformally different from the gasket limit set of a geometrically finite Kleinian group.

Submitted 19 February, 2024; originally announced February 2024.

*Böttcher coordinates at wild superattracting fixed points*

Let p be a prime number, let g(x)=xp2+pr+2xp2+1 with r∈ℤ≥0, and let ϕ(x)=x+O(x2) be the Böttcher coordinate satisfying ϕ(g(x))=ϕ(x)p2. Salerno and Silverman conjectured that the radius of convergence of ϕ−1(x) in ℂp is p−p−r/(p−1). In this article, we confirm that this conjecture is true by showing that it is a special case of our more general result.

*Antiholomorphic correspondences and mating I: realization theorems*

In this paper, we study the dynamics of a general class of antiholomorphic correspondences; i.e., multi-valued maps with antiholomorphic local branches, on the Riemann sphere. Such correspondences are closely related to a class of single-valued antiholomorphic maps in one complex variable; namely, Schwarz reflection maps of simply connected quadrature domains. Using this connection, we prove that matings of all parabolic antiholomorphic rational maps with connected Julia sets (of arbitrary degree) and antiholomorphic analogues of Hecke groups can be realized as such correspondences. We also draw the same conclusion when parabolic maps are replaced with critically non-recurrent antiholomorphic polynomials with connected Julia sets.

arXiv:2303.02459 |

*Bounded Fatou and Julia components of meromorphic functions*

Abstract: We completely characterise the bounded sets that arise as components of the Fatou and Julia sets of meromorphic functions. On the one hand, we prove that a bounded domain is a Fatou component of some meromorphic function if and only if it is regular. On the other hand, we prove that a planar continuum is a Julia component of some meromorphic function if and only if it has empty interior. We do so by constructing meromorphic functions with wandering continua using approximation theory.

*Circle packings, renormalizations and subdivision rules*

In this paper, we use iterations of skinning maps on Teichmüller spaces to study circle packings. This allows us to develop a renormalization theory for circle packings whose nerves satisfy certain subdivision rules. We characterize when the skinning map has bounded image. Under the corresponding condition, we prove that the renormalization operator is uniformly contracting. This allows us to give complete answers for the existence and moduli problems for such circle packings. The exponential contraction has many consequences. In particular, we prove that homeomorphisms between any two such circle packings are asymptotically conformal.

*MLC at Feigenbaum points*

We prove {\em a priori} bounds for Feigenbaum quadratic polynomials, i.e., infinitely renormalizable polynomials fc:z↦z2+c of bounded type. It implies local connectivity of the corresponding Julia sets J(fc) and MLC (local connectivity of the Mandelbrot set $\Mandel$) at the corresponding parameters c. It also yields the scaling Universality, dynamical and parameter, for the corresponding combinatorics. The MLC Conjecture was open for the most classical period-doubling Feigenbaum parameter as well as for the complex tripling renormalizations. Universality for the latter was conjectured by Goldberg-Khanin-Sinai in the early 1980s.

*Mirrors of conformal dynamics: Interplay between anti-rational maps, reflection groups, Schwarz reflections, and correspondences*

The goal of this survey is to present intimate interactions between four branches of conformal dynamics: iterations of anti-rational maps, actions of Kleinian reflection groups, dynamics generated by Schwarz reflections in quadrature domains, and algebraic correspondences. We start with several examples of Schwarz reflections as well as algebraic correspondences obtained by matings between anti-rational maps and reflection groups, and examples of Julia set realizations for limit sets of reflection groups (including classical Apollonian-like gaskets). We follow up these examples with dynamical relations between explicit Schwarz reflection parameter spaces and parameter spaces of anti-rational maps and of reflection groups. These are complemented by a number of general results and illustrations of important technical tools, such as David surgery and straightening techniques. We also collect several analytic applications of the above theory

*Structure of hyperbolic polynomial automorphisms of C^2 with disconnected Julia sets*

For a hyperbolic polynomial automorphism of C^2 with a disconnected Julia set, and under a mild dissipativity condition, we give a topological description of the components of the Julia set. Namely, there are finitely many "quasi-solenoids" that govern the asymptotic behavior of the orbits of all non-trivial components. This can be viewed as a refined Spectral Decomposition for a hyperbolic map, as well as a two-dimensional version of the (generalized) Branner-Hubbard theory in one-dimensional polynomial dynamics. An important geometric ingredient of the theory is a John-like property of the Julia set in the unstable leaves.

*Berkovich dynamics of twisted rational maps*

A twisted rational map over a non-archimedean field K is the composition of a rational function over K and a continuous automorphism of K. We explore the dynamics of some twisted rational maps on the Berkovich projective line.