Resolvent, spectrum and resonances for the acoustic operator with piecewise constant coefficients

Andrea Mantile, Andrea Posilicano

We study the acoustic operator $A_{v,\ddot{I}}:=v^2\ddot{I}\nabla \cdot \ddot{I}{}^{-1}\nabla$ with transmission conditions at the boundary of $\hat{I}\text{c◯}=\hat{I}{\text{c◯}}_1\cup \cdots \cup \hat{I}{\text{c◯}}_n$, where the $\hat{I}{\text{c◯}}_{\ell }$'s…