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# Wydawnictwa / Czasopisma IMPAN / Fundamenta Mathematicae / Wszystkie zeszyty

## A parabolic Pommerenke–Levin–Yoccoz inequality

### Tom 172 / 2002

Fundamenta Mathematicae 172 (2002), 249-289 MSC: Primary 37F10; Secondary 30D05, 37F45. DOI: 10.4064/fm172-3-3

#### Streszczenie

In a recent preprint [B], Bergweiler relates the number of critical points contained in the immediate basin of a multiple fixed point $\beta$ of a rational map $f: {\mathbb P}^1\to {\mathbb P}^1$, the number ${N}$ of attracting petals and the residue $\iota (f,\beta )$ of the 1-form $dz/(z-f(z))$ at $\beta$. In this article, we present a different approach to the same problem, which we were developing independently at the same time. We apply our method to answer a question raised by Bergweiler. In particular, we prove that when there are only ${N}$ grand orbit equivalence classes of critical points in the immediate basin, then $$\Re ((N+1)/{2}-\iota (f,\beta )) > N/{\pi ^2}.$$

#### Autorzy

• Xavier BuffLaboratoire Émile Picard
Université Paul Sabatier
31062 Toulouse Cedex, France
e-mail