On convergence to the Denjoy-Wolff point
Bourdon, P. S. ; Matache, V. ; Shapiro, J. H.
Illinois J. Math., Tome 49 (2005) no. 2, p. 405-430 / Harvested from Project Euclid
For holomorphic selfmaps of the open unit disc $\U$ that are not elliptic automorphisms, the Schwarz Lemma and the Denjoy-Wolff Theorem combine to yield a remarkable result: each such map $\phi$ has a (necessarily unique) ``Denjoy-Wolff point'' $\dwp$ in the closed unit disc that attracts every orbit in the sense that the iterate sequence $(\phin)$ converges to $\dwp$ uniformly on compact subsets of $\U$. In this paper we prove that, except for the obvious counterexamples—inner functions having $\dwp\in\U$—the iterate sequence exhibits an even stronger affinity for the Denjoy-Wolff point; $\phin\goesto\dwp$ in the norm of the Hardy space $H^p$ for $1\le p<\infty$. For each such map, some subsequence of iterates converges to $\dwp$ almost everywhere on $\bdu$, and this leads us to investigate the question of almost-everywhere convergence of the entire iterate sequence. Here our work makes natural connections with two important aspects of the study of holomorphic selfmaps of the unit disc: linear-fractional models and ergodic properties of inner functions.
Publié le : 2005-04-15
Classification:  30D05,  28D99,  37A05,  37F10
@article{1258138025,
     author = {Bourdon, P. S. and Matache, V. and Shapiro, J. H.},
     title = {On convergence to the Denjoy-Wolff point},
     journal = {Illinois J. Math.},
     volume = {49},
     number = {2},
     year = {2005},
     pages = { 405-430},
     language = {en},
     url = {http://dml.mathdoc.fr/item/1258138025}
}
Bourdon, P. S.; Matache, V.; Shapiro, J. H. On convergence to the Denjoy-Wolff point. Illinois J. Math., Tome 49 (2005) no. 2, pp.  405-430. http://gdmltest.u-ga.fr/item/1258138025/