A Laplace transform of irregular growth
Jan Wiegerinck
TL;DR
This paper constructs an explicit example of a Laplace transform $\int_\gamma e^{zs} d\mu(s)$ with irregular growth, answering Korevaar’s question in Hayman’s List. It does so by building a canonical product whose zeros lie on circles of radius $2^k$, giving an exponential-type function with indicator $h(\theta)=2$, and then expressing the function via its Borel transform and a contour integral. By decomposing the transform into a bounded part and a remainder and demonstrating that the remainder cannot have regular growth, the work establishes the existence of a Laplace transform of irregular growth despite controlled exponential-type behavior. The result clarifies the distinction between regular and irregular growth in Laplace-type representations and highlights the intricate role of zero distribution and Borel transforms in growth properties of entire functions.
Abstract
We give an example of a Laplace transform $\int_γe^{ζz} dμ(ζ)$ that does not have regular growth. This answers a question in Hayman's List
