branching process human population Malthusian parameter
Institute of Mathematics and Informatics at the Bulgarian Academy of Sciences
Pliska Studia Mathematica Bulgarica, Vol. 24, No 1, (2015), 99p-110p
The Crump-Mode-Jagers branching process is used to model the populations of Bulgaria, Greece, Ireland, Italy, Portugal and Spain, which were influenced greatly by the economic crisis, started in 2008. The social effects were felt shortly after 2008 with different delay for each country. The unemployment rate in some of these countries was very high and constituted mainly of young people around 25 years old. This paper reviews the demographic changes that were experienced during the crisis and its effect on population growth. It also reviews the current retirement policy in these countries and extrapolates the needed changes in order to keep the current percentage of working people constant. 2010 Mathematics Subject Classification: 60J85, 92D25.