It is well known that spectra in classical fluids at equilibrium decay faster than any power of ω for high frequency. It is suggested that the ultimate decay is exponential for finite systems but slower than any exponential in infinite fluids. This renders time series in finite systems...

We study the model of interacting agents proposed by Chakraborti and Chakrabarti [Eur. Phys. J. B 17 (2000) 167] that allows agents to both save and exchange wealth. Closed equations for the wealth distribution are developed using a mean field approximation.