Multipoint Julia theorems
Speaker:
Marco Abate, Università di Pisa
Date and Time:
Monday, May 30, 2022 - 9:00am to 10:00am
Location:
Fields Institute, Room 230
Abstract:
Following ideas introduced by Beardon-Minda and by Baribeau-Rivard-Wegert in the context of the Schwarz-Pick lemma, we use the iterated hyperbolic difference quotients to prove a multipoint Julia lemma. As applications, we give a sharp estimate from below of the angular derivative at a boundary point, recovering in this setting a formula very recently proved by Fournier and Roth and generalizing results due to Osserman, Mercer and others; and we prove a generalization to multiple fixed points of an interesting estimate due to Cowen and Pommerenke.