Tatsuo Nishitani

collaborators

2 papers

math.AP2022

A note on the Cauchy problem for $- D_{0}^{2} + 2 x_{1} D_{0} D_{2} + D_{1}^{2} + x_{1}^{3} D_{2}^{2} + \sum_{j = 0}^{2} b_{j} D_{j}$

Tatsuo Nishitani

In this note, we improve a previously proven non-solvability result of the Cauchy problem for the Cauchy problem in the Gevrey class for a homogeneous second-order differential ope…

math.AP2014

Counterexamples to $C^{\infty}$ well posedness for some hyperbolic operators with triple characteristics

Enrico Bernardi, Tatsuo Nishitani

In this paper we prove that for a class of non-effectively hyperbolic operators with smooth triple characteristics the Cauchy problem is well posed in the Gevrey 2 class, beyond th…

A note on the Cauchy problem for −D02​+2x1​D0​D2​+D12​+x13​D22​+∑j=02​bj​Dj​

Counterexamples to C∞ well posedness for some hyperbolic operators with triple characteristics

A note on the Cauchy problem for $- D_{0}^{2} + 2 x_{1} D_{0} D_{2} + D_{1}^{2} + x_{1}^{3} D_{2}^{2} + \sum_{j = 0}^{2} b_{j} D_{j}$

Counterexamples to $C^{\infty}$ well posedness for some hyperbolic operators with triple characteristics