Numerical and theoretical investigations of species evolution in presence of extinction rules are recalled in the framework of punctuated equilibrium evolution models. Previous results, on the Bak–Sneppen model are mentioned together with extensions taking into account a variable number of...

The Zipf analysis of n-words in random sequences and financial data series like the stock prices of a company has been performed. The bias as well as the resulting staircase structure of the Zipf plots are taken into account in the subsequent analysis. It is found that correlations for the sign...