  Entanglement of a macroscopic system with a microscopic one is shown to begin
by a topological property of histories in the Feynman formulation of quantum
mechanics. This property can also be expressed algebraically on the
Schr\"odinger equation through a convenient extension of the Hilbert space
formalism. Entanglement shows then properties of growth and transport, the
corresponding local and temporary character of entanglement being called here
"intricacy" when it occurs. When applied to the continuous interaction of a
macroscopic system with a random environment, intricacy implies a
"predecoherence" effect, which can generate and transport permanently
incoherence within the system. The possible relevance of these results for a
theory of wave function collapse is also indicated.
