Weakly hyperbolic equations with time degeneracy in Sobolev spaces
Weakly hyperbolic equations with time degeneracy in Sobolev spaces
The theory of nonlinear weakly hyperbolic equations was developed during the last decade in an astonishing way. Today we have a good overview about assumptions which guarantee local well posedness in spaces of smooth functions ( C ∞ , Gevrey). But the situation is completely unclear in the case of …