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arXiv 1404.4471math.AP
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具有临界指数的高维半线性wave equations的几乎整体解

Almost global solutions of semilinear wave equations with the critical exponent in high dimensions

Hiroyuki Takamura, Kyouhei Wakasa

摘要:

本文主要研究非线性波动方程一般理论中经典解的“几乎”整体存在性。所有这三种情况都是尖锐的,因为模型方程在临界情况下会出现爆破结果。然而,如果非线性项是未知函数的导数,并且满足所谓的零条件,即非正条件,那么在低维空间中,我们有可能得到其中两个方程的整体时解存在性。但另一个四维空间中的二次项则不适用,因为非线性项应该包括未知函数本身的平方。在本文中,我们得到了一个例子,保证了在四维空间中几乎全球时间存在的清晰度。这也是第一个在高维空间中对非单项和不定符号项的经典解爆破的例子。这一项是由于忽略了Duhamel公式中的导数损失因子而产生的。这一事实可以帮助我们描述一个标准,以获得全球的时间存在,在这种关键情况下。

英文摘要:

We are interested in the "almost" global-in-time existence of classical solutions in the general theory for nonlinear wave equations. All the three such cases are known to be sharp due to blow-up results in the critical case for model equations. However, it is known that we have a possibility to get the global-in-time existence for two of them in low space dimensions if the nonlinear term is of derivatives of the unknown function and satisfies so-called null condition, or non-positive condition. But another one for the quadratic term in four space dimensions is out of the case as the nonlinear term should include a square of the unknown function itself. In this paper, we get one more example guaranteeing the sharpness of the almost global-in-time existence in four space dimensions. It is also the first example of the blow-up of classical solutions for non-single and indefinitely signed term in high dimensions. Such a term arises from the neglect of derivative-loss factors in Duhamel's formula for positive and single nonlinear term. This fact may help us to describe a criterion to get the global-in-time existence in this critical situation.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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