The simple branching process with infinite mean. I

Abstract

The simple branching process {Zn } with mean number of offspring per individual infinite, is considered. Conditions under which there exists a sequence {pn } of positive constants such that pn log (1 +Zn ) converges in law to a proper limit distribution are given, as is a supplementary condition necessary and sufficient for pn~ constant cn as n→∞, where 0 < c < 1 is a number characteristic of the process. Some properties of the limiting distribution function are discussed; while others (with additional results) are deferred to a sequel.