  Our account of the problem of the classical limit of quantum mechanics
involves two elements. The first one is self-induced decoherence, conceived as
a process that depends on the own dynamics of a closed quantum system governed
by a Hamiltonian with continuous spectrum; the study of decoherence is
addressed by means of a formalism used to give meaning to the van Hove states
with diagonal singularities. The second element is macroscopicity: when the
macroscopic limit is applied to the Wigner transformation of the diagonal state
resulting from decoherence, the description of the quantum system becomes
equivalent to the description of an ensemble of classical trajectories on phase
space weighted by their corresponding probabilities.
