On weakly hyperbolic operators with non-regular coefficients and finite order degeneration. (Q1399403)

The Gevrey well posedness of the Cauchy problem for a second order degenerate equation is studied. The coefficients of the operator are functions of the time variable only. A number of cases are considered, each allowing some degeneracy with respect to the time variable. The authors prove a number of theorems concerning the Gevrey exponent \(s_0\) such that the Cauchy problem is well posed for every \(s\), \(1 \leq s < s_0\).