In this paper, the authors explain the notion of long memory and report their results concerned with the long memory properties of trading volume and the volatility of stock returns (given by absolute returns and alternatively by square returns) of American companies listed in DJIA index. The...

We recall the historical changes that have taken place in the power markets worldwide and that have led to a partial or full opening for competition. Afterwards we discuss power market structure with special emphasis on differences between financial or other commodity markets on one hand and the...