Galton-Watson process
The Galton-Watson process belongs to family stochastic processes which explain the evolution of a population. A common application of this process is in the evolution of family tree. The problem is articulated as follows: Suppose that each individual of a population gives birth to a random number of children. The distribution probability of the random number of children, called the offspring distribution, is the same for all the individuals. The problematic is to know the probability that a given family line dies out.