论文标题
关于弱双曲方程的Gevrey类中凯奇问题的问题
A question on the Cauchy problem in the Gevrey classes for weakly hyperbolic equations
论文作者
论文摘要
对于带有gevrey系数的均质多项式$ p $ in {\ bf r}^n $，众所周知，如果$ p $实现$ p $的cauchy问题，则在Gevrey类$ s <2 $中，如果特征性的起源是真实的。在本说明中，我们举例说明了相反方向的情况，特别是Gevrey订单$ s = 2 $的最佳性。
For a homogeneous polynomial $p$ in $ξ\in {\bf R}^n$ with Gevrey coefficients, it is known that the Cauchy problem for any realization of $p$ is well-posed in the Gevrey class of order $s<2$ if the characteristic roots are real. In this note, we give examples showing the situation of the converse direction, in particular the optimality of the Gevrey order $s=2$.
