Local existence for the linearized compressible Euler equation with a free boundary Uwe Brauer∗ and Gabriel Nagy† ∗ Departamento † Gabriel de Matemática Aplicada, Universidad Complutense, Madrid Nagy Department of Mathematics, Michigan State University Abstract An initial free-boundary problem for the compressible Euler equation is considered, in order to describe the time evolution of a body with a sharp boundary. Our approach is as follows. First, we transform the free–boundary problem into a fixedboundary problem in the usual way by using the Lagrange formulation of Euler’s equations. We then write the resulting system as a first order system of evolution and constraint equations. We then apply known results for initial fixed-boundary value problem using maximal dissipative boundary conditions. The treatment of the constraints at the boundary turns out to be the most difficult part of our approach. 1