We study the scaling behavior in currency exchange rates. Our results suggest that they satisfy scaling with an exponent close to 0.5, but that it differs qualitatively from that of a simple random walk. Indeed price variations cannot be considered as independent variables and subtle...

The problem of the stretching of material lines and surfaces in fluids described by simple Lagrangian equations is revised using methods and tools borrowed from the theory of dynamical systems. The approach allows us to show that some results, previously obtained in the theory of developed...