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## VI. CONCLUSIONS AND DISCUSSIONS 

Assuming first that DE component is homogeneous, we have investigated how DM approaches the dynamical equilibrium in the collapsing system. In the presence of coupling between DE and DM, the flow of mass and energy between the components changes the time required by the system to reach equilibrium and also the equilibrium configuration itself. Our discussion is based on the perturbation theory developed in [8, 19]. We reproduce the 

