Relativistic elastodynamics
  There are many different formulations of relativistic elasticity. Most of them are only concerned with formal questions rather than questions regarding the PDE point of view. The aim of this thesis is to obtain various local existence results for dynamical scenarios involving elastic matter. Following Beig and Schmidt we treat relativistic elasticity as a Lagrangian field theory. The basic unknowns are mappings between spacetime and an abstract material manifold. The equations of motion will be the Euler-Lagrange equations arising from the action principle. Under certain (physically reasonable) restrictions on the elastic properties of the material the resulting system is hyperbolic and local existence results can be derived. This way we can show well-posedness for the equations describing elastic matter on a fixed gravitational background, self-gravitating elastic matter and a finite elastic body on a fixed background. The thesis also contains some results on energy conservation and on linearized elasticity. 
Michael Wernig-Pichler