Fractal functions with no radial limits in Bergman spaces on trees

Abstract

For each $p \gt 0$ we provide the construction of a harmonic function on a homogeneous isotropic tree $T$ in the Bergman space $A^p(\sigma)$ with no finite radial limits anywhere. Here, $\sigma$ is an analogue of the Lebesgue measure on the tree. With the appropriate modifications, the construction yields a function in $A^1(\sigma)$ when $T$ is a rooted radial tree such that the number of forward neighbors increases so slowly that their reciprocals are not summable.