The location of invariant tori for a two-dimensional Hamiltonian mapping exhibiting mixed phase space is discussed. The phase space of the mapping shows a large chaotic sea surrounding periodic islands and limited by a set of invariant tori. Given the mapping considered is parameterised by an...

In this work we study an unusual phase transition of the Baxter–Wu model in the presence of an external magnetic field. The model is pure Baxter–Wu, which means that only three-spin interactions are taken into account. We construct a phase diagram on the temperature–field plane based...

In this work we study the existence of nontrivial solution for the following class of multivalued quasilinear problems <Equation ID="Equ51"> <EquationSource Format="TEX">$$\begin{aligned} \displaystyle -\text{ div } ( \phi (|\nabla u|) \nabla u) - b(u)u \in \lambda \partial F(x,u)\;\text{ in }\;\Omega , \quad u=0\; \text{ on }\;\partial \Omega...</equationsource></equation>

This paper discusses various ways of measuring the persistence or Long Memory (LM) of financial market risk in both its time and frequency domains. For the measurement of the risk, irregularity or 'randomness' of these series, we can compute a set of critical Lipschitz - Hölder exponents, in...