On the Cauchy problem for noneffectively hyperbolic operators: The Gevrey 4 well-posedness
On the Cauchy problem for noneffectively hyperbolic operators: The Gevrey 4 well-posedness
For a hyperbolic second-order differential operator P, we study the relations between the maximal Gevrey index for the strong Gevrey well-posedness and some algebraic and geometric properties of the principal symbol p. If the Hamilton map Fp of p (the linearization of the Hamilton field Hp along double characteristics) has …