“…In the theory developed in [22,33], the internal energy and the heat flux are described as functionals of u and u x . The following system [7,28,23,12] has been frequently used to describe this phenomena, (1.2) ∂ ∂t u(t, x) + Here, Ω ⊂ R n is open, bounded and has smooth boundary, (t; x) ∈ [0; ∞) × Ω, u(t; x) represents the temperature in x at the time t, c is a physical constant and k i : R → R, i = 1, 2, are the internal energy and the heat flux relaxation respectively. By assuming that the solution u(.)…”