Connectedness properties of the set where the iterates of an entire function are unbounded

Abstract

We investigate the connectedness properties of the set $ I^{\!+\!}(f) $ of points where the iterates of an entire function $ f $ are unbounded. In particular, we show that $ I^{\!+\!}(f) $ is connected whenever iterates of the minimum modulus of $ f $ tend to infinity. For a general transcendental entire function $ f $, we show that $ I^{\!+\!}(f) \cup \lbrace \infty \rbrace $ is always connected and that, if $ I^{\!+\!}(f) $ is disconnected, then it has uncountably many components, infinitely many of which are unbounded.