This paper deals with the model proposed for nonsimple materials with heat conduction of type III. We analyze first the general system of equations, determine the behavior of its solutions with respect to the time and show that the semigroup associated with the system is not analytic. Two limiting cases of the model are studied later.

We compare systematically several classes of stochastic volatility models of stock market fluctuations. We show that the long-time return distribution is either Gaussian or develops a power-law tail, while the short-time return distribution has generically a stretched-exponential form, but can assume also an algebraic decay, in the family of models which we call “GARCH”-type. The intermediate r...

Let G be a graph and S ⊆ V (G). For each vertex u ∈ S and for each v ∈ V (G) − S, we define d(u, v) = d(v, u) to be the length of a shortest path in 〈V (G)−(S−{u})〉 if such a path exists, and∞ otherwise. Let v ∈ V (G). We define wS(v) = ∑ u∈S 1 2d(u,v)−1 if v 6∈ S, and wS(v) = 2 if v ∈ S. If, for each v ∈ V (G), we have wS(v) ≥ 1, then S is an exponential dominating set. The smallest cardinalit...

We study the asymptotic behavior of the solution of the Maxwell equations with the following boundary condition of memory type Eτ (t) = η0H(t)× n + ∫ ∞ 0 η(s)H(t− s)× n ds. We consider a ‘Graffi’ type free energy and we prove that, if the kernel η satisfies the condition η′′ + κ η′ > 0 and the domain Ω is strongly star shaped, then the energy of the solution exponentially decays. We also prove ...