Radial growth, Lipschitz and Dirichlet spaces on solutions to the Yukawa equation

In this paper, we investigate some properties to solutions $f$ to the Yukawa PDE: $\Delta f=\lambda f$ in the unit ball $\mathbb{B}^n$ of $\mathbb{C}^n$, where $\lambda$ is a nonnegative constant. First, we prove that the answer to an open problem of Girela and Pel\'{a}ez, concerning such solutions, is positive. Then we study relationships on such solutions between the bounded mean oscillation and Lipschitz-type spaces. At last, we discuss Dirichlet-type energy integrals on such solutions in the unit ball of $\mathbb{C}^{n}$ and give an application.