Two-Sex Galton-Watson Branching Processes

Ali Falahati

Dept of Math Statistics, Chalmers Univ of Technology, Gothenburg, Sweden

Abstract

In this talk we present a model for studying a bisexual population called Two-Sex Galton-Watson Branching Processes (2S-GWBP for short). Our model follows that of Asmussen and Hering (1983), where population developments proceeds in two stages, first reproduction and then mating. Our model, emphasizes on the notion of the family, i. e. children born from a couple (or a mating unite). The total number of couples in a coming generation will be the sum of marriages of daughters of each family. In the model studied by Asmussen and Hering (1983), it is the total numbers of the female and male in the present generation which determine the distribution of number of the couples in the coming generation, where in our model we allow this distribution depends not only on the number of couples in the present generation but also to a suitable function of size of all families in that generation. Also in our model we allow the distribution of number of children born into each family depends on the number of family (or couples) of that generation. The results for a simple case both for a supercritical and critical case will be given.