A generalization of the Gurtin{MacCamy model for an S{I{R epidemic is described. The new model, which includes di usion away from overcrowded regions, retains many of the interesting qualitative features of previous models. In addition, the global{in{time existence of solutions is proved for a special case. Qualitative properties of the solution are discussed and illustrated with a numerical ex...

In this paper, we propose to study the interest of relaxing qualitative constraints networks by using the formalism of discrete Constraint Satisfaction Problem (CSP). This allows us to avoid the introduction of new definitions and properties in the domain of qualitative reasoning. We first propose a general (but incomplete) approach to show the unsatisfiability of qualitative networks, by using...

We study qualitative properties for nonnegative solutions to a conformally invariant coupled system of fourth order equations involving critical exponents. For defined in the punctured space, there exist essentially two cases analyze. If origin is removable singularity, we use an integral moving spheres method prove that non-singular are rotationally invariant. More precisely, they product sphe...