  The Continuous Time Random Walk (CTRW) formalism is used to model the
non-Poisson relaxation of a system response to perturbation. Two mechanisms to
perturb the system are analyzed: a first in which the perturbation, seen as a
potential gradient, simply introduces a bias in the hopping probability of the
walker from on site to the other but leaves unchanged the occurrence times of
the attempted jumps ("events") and a second in which the occurrence times of
the events are perturbed. The system response is calculated analytically in
both cases in a non-ergodic condition, i.e. for a diverging first moment in
time. Two different Fluctuation-Dissipation Theorems (FDTs), one for each kind
of mechanism, are derived and discussed.
