Summary: Some two-dimensional and three-dimensional stochastic processes concerning birth, death and migration phenomena with acquisition of permanent character are investigated. The mathematical solutions of the above mentioned processes present outstanding curiosities.
A population theory problem which is solvable through a system of two linear differential equations with random initial conditions is also presented. These results have applications in the study of dynamical populations in both physics and biology. The law of almost-sure events is finally obtained as the inverse of the odds events law of Poisson.