We investigate the well known Newton method to find roots of entire holomorphic functions. Our main result is that the immediate basin of attraction for every root is simply connected and unbounded. We also introduce “virtual immediate basins” in which the dynamics converges to infinity; we prove that these are simply connected as well.

Nous considérons un germe de feuilletage holomorphe singulier non-dicritique $ℱ$ défini sur une boule fermée $\overline{𝔹}\subset {ℂ}^2$, satisfaisant des hypothèses génériques, de courbe de séparatrice $S$. Nous démontrons l’existence d’un voisinage ouvert $U$ de $S$ dans $\overline{𝔹}$ tel que, pour toute feuille $L$ de ${ℱ}_{\left|\right(U\setminus S)}$, l’inclusion naturelle $ı:L\hookrightarrow U\setminus S$ induit un monomorphisme ${ı}_{*}:{\pi }_1\left(L\right)\hookrightarrow {\pi }_1(U\setminus S)$ au niveau du groupe fondamental. Pour cela, nous introduisons la notion géométrique de « connexité feuilletée » avec laquelle nous réinterprétons la notion d’incompressibilité....

This paper is motivated by the problem of dependence of the Hausdorff dimension of the Julia-Lavaurs sets $J_{0,\sigma }$ for the map f₀(z) = z²+1/4 on the parameter σ. Using homographies, we imitate the construction of the iterated function system (IFS) whose limit set is a subset of $J_{0,\sigma }$, given by Urbański and Zinsmeister. The closure of the limit set of our IFS ${\varphi }_{\sigma ,\alpha }^{n,k}$ is the closure of some family of circles, and if the parameter σ varies, then the behavior of the limit set is similar to the behavior of $J_{0,\sigma }$. The parameter...

In this paper we show that if $v$ is an analytic vector field on ${ℝ}^3$ having an isolated singular point at 0, then there exists a trajectory of $v$ which converges to 0 in the past or in the future. The proof is based on certain results concerning desingularizaton of vector fields in dimension three and on index-type arguments à la Poincaré-Hopf.

We show how the well-known concept of external rays in polynomial dynamics may be extended throughout the Julia set of certain rational maps. These new types of rays, which we call internal rays, meet the Julia set in a Cantor set of points, and each of these rays crosses infinitely many other internal rays at many points. We then use this construction to show that there are infinitely many disjoint copies of the Mandelbrot set in the parameter planes for these maps.

Jordan analytic curves which are invariant under rational functions are studied.