Séminaire du pôle analyse 17/12 : Xavier Claeys (ENSTA Paris)

Abstract: We consider the Helmholtz equation posed in the exterior of a surface with multiple branches. Stemming from a simple caracterization of trace spaces as quotients of volume based Sobolev spaces, we shall present a complete framework that allows Green formulas, representation formulas, layer potentials/boundary integral operators and jump formulas. We will discuss concrete applications of this framework to scattering by so-called multi-screens that consist in arbitrary arrangements of screens with multiple branches.