Exponential polynomials with Baker omitted value

Abstract

We consider exponential polynomials of the form $F_l(z)=P_1(z)\exp(Q_1(z))+P_2(z)\exp(Q_2(z))+\cdots+P_{l-1}(z)\exp(Q_{l-1}(z))+P_l(z)$, where $l\geq2$, each $Q_i$ is a non-constant polynomial and each $P_i$, $i=1,2,\ldots,l-1$, is a polynomial (possibly constant), while $P_l$ is a non-constant polynomial. This article studies the topology of the preimages under $F_l$ of neighborhoods of the essential singularity at infinity. We prove that for each neighbourhood $D$ of infinity, the set $F_l ^{-1} (D) $ is connected, and in fact is an infinitely connected domain with all its boundary components bounded. In such a situation, the point at $\infty$ is called the Baker omitted value of the function. Our methods significantly extend those developed by Das and Nayak (in Complex Var. Elliptic Equ. 70:1831-1847, 2025), providing a broader framework for the study of this phenomenon. We further show that these functions do not admit any Baker wandering domain and hence every Fatou component is simply connected. Finally, we conclude by posing some problems arising out of this work.