We construct examples of twice differentiable functions in \({\mathbb {R}}^n\) with continuous Laplacian and unbounded Hessian. The same construction is also applicable to higher order differentiability.

中文翻译：

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具有连续拉普拉斯算子和无界 Hessian 算子的二次可微函数示例

我们在\({\mathbb {R}}^n\)中构造具有连续拉普拉斯算子和无界 Hessian 算子的二次可微函数示例。同样的构造也适用于高阶可微性。