Abstract (eng)
Sobolev spaces play a key role in the proof of existence of solutions to linear symmetric
hyperbolic systems and in the proof of local existence of solutions to non linear wave
equations. Here we prove the existence and uniqueness of solutions to linear symmetric
hyperbolic systems. We describe basic properties and prove important estimates of
Sobolev spaces. By using the exact form of the duality we prove existence of solutions
to linear symmetric hyperbolic systems. By the Sobolev embedding inequality we can
connect the regularity of Sobolev spaces with classical differentiability. Consequently, we
can obtain k times continuously differentiable or even smooth solutions.