Small positive values and limit theorems for supercritical branching processes with immigration in random environment

Let (Zₙ) be a supercritical branching process with immigration in a random environment. The small positive values and some lower deviation inequalities for Z are investigated. Based on these results, the central limit theorem of Zₙ and the Edgeworth expansion are obtained. The study is taken under the assumption that each individual produces 0 offspring with a positive probability.