“…Then the study of their statistics will follow the usual steps for purely classical or purely quantum ensembles. In this respect, it should be noted that other approaches to MQCD (not based on Ehrenfest equations) exist [19,20,21], and to their corresponding statistics [22,23], however it has been found that the formulation of well defined quantum-classical brackets (i.e., satisfying the Jacobi identity and Leibniz derivation rule) is a difficult issue [24,25,26,27]. On the contrary, as shown below, and as a result of the fact that the evolution of a quantum system can be formulated in terms of Hamilton equations similar to those of a classical system [4,28], we will not have difficulties in a rigorous formulation of the Ehrenfest dynamics in terms of Poisson brackets.…”