This paper considers the use of the long-memory, semi-parametric estimators to test unit-root and non-cointegrated processes under fractional alternatives. Critical-point values of the proposed tests are given for different sample sizes. The ADF test is used for comparison purposes. The...

We argue that two main ingredients in agent-based models (and in real speculative markets) which lead to realistic behavior of prices and trading volume are : heterogeneity (given the same source of information, market participants do not behave identically) and feedback (the individual demand...