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arXiv 1408.3499math.AP
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具有不定常传播速度和强阻尼的线性双曲型方程

Linear hyperbolic equations with time-dependent propagation speed and strong damping

Marina Ghisi, Massimo Gobbino

摘要:

考虑弹性算子前具有不定常系数c(t)的二阶线性方程。对于这些方程,众所周知,初始数据的较高空间正则性补偿了c(t)的较低时间正则性。在本文中,我们调查的影响,一个强大的耗散,即摩擦项,它取决于一个权力的弹性运营商。我们发现的是阈值效应。当摩擦项中的弹性算子的指数大于1/2时,阻尼占优势,并且方程表现得好像系数c(t)是常数。当指数小于1/2时,c(t)的时间规律性开始起作用。如果c(t)足够规则,阻尼再次占优势。相反,当c(t)不够规则时,阻尼可能是无效的,并且有耗散方程表现为非耗散方程的例子。正如预期的那样,阻尼越强,时间规律性阈值越低。我们还提供了反例显示我们的结果的最优性。

英文摘要:

We consider a second order linear equation with a time-dependent coefficient c(t) in front of the "elastic" operator. For these equations it is well-known that a higher space-regularity of initial data compensates a lower time-regularity of c(t). In this paper we investigate the influence of a strong dissipation, namely a friction term which depends on a power of the elastic operator. What we discover is a threshold effect. When the exponent of the elastic operator in the friction term is greater than 1/2, the damping prevails and the equation behaves as if the coefficient c(t) were constant. When the exponent is less than 1/2, the time-regularity of c(t) comes into play. If c(t) is regular enough, once again the damping prevails. On the contrary, when c(t) is not regular enough the damping might be ineffective, and there are examples in which the dissipative equation behaves as the non-dissipative one. As expected, the stronger is the damping, the lower is the time-regularity threshold. We also provide counterexamples showing the optimality of our results.

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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