arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2005.08811math.APmath.FA
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退火Calderon-Zygmund估计作为定量随机均匀化的方便工具

The annealed Calderon-Zygmund estimate as convenient tool in quantitative stochastic homogenization

Marc Josien, Felix Otto

摘要:

本文研究了具有随机系数的散度型线性椭圆型方程的定量均匀化理论。我们得到梯度估计的均匀化误差,即在实际的解决方案和两个规模的扩展的均匀化解决方案之间的差异,无论是在强规范(振荡)和弱规范(波动)。这些估计是最佳的尺度之间的比例在微观和宏观尺度。本文的目的是突出使用最近推出的退火Calderon-Zygmund(CZ)估计在获得上述,以前已知的,误差估计。此外,本文提供了一个新的证明,这些退火CZ估计,完全避免淬火正则性理论,而是依赖于泛函分析。它是基于这样的观察,即即使在算子范数的水平上,亥姆霍兹投影也接近于均匀化系数的投影(对于均匀化系数,退火CZ估计很容易获得)。在这篇文章中,我们力求简单的证明,从而限制自己的系综系数场的局部变换的高斯随机场与可积相关和Hölder连续实现。在早期的工作中,我们使用的自然对象的一般理论的均匀化,如(潜在的和通量)校正和均匀化换向器。振荡和波动估计都依赖于灵敏度演算,即估计感兴趣的量对系数场中的无穷小变化的敏感程度,该系数场被馈送到谱隙不等式中。在这篇文章中,退火CZ估计是椭圆正则性理论进入的唯一形式。

英文摘要:

This article is about the quantitative homogenization theory of linear elliptic equations in divergence form with random coefficients. We derive gradient estimates on the homogenization error, i.e. on the difference between the actual solution and the two-scale expansion of the homogenized solution, both in terms of strong norms (oscillation) and weak norms (fluctuation). These estimates are optimal in terms of scaling in the ratio between the microscopic and the macroscopic scale. The purpose of this article is to highlight the usage of the recently introduced annealed Calderon-Zygmund (CZ) estimates in obtaining the above, previously known, error estimates. Moreover, the article provides a novel proof of these annealed CZ estimate that completely avoids quenched regularity theory, but rather relies on functional analysis. It is based on the observation that even on the level of operator norms, the Helmholtz projection is close to the one for the homogenized coefficient (for which annealed CZ estimates are easily obtained). In this article, we strive for simple proofs, and thus restrict ourselves to ensembles of coefficient fields that are local transformations of Gaussian random fields with integrable correlations and Hölder continuous realizations. As in earlier work, we use the natural objects from the general theory of homogenization, like the (potential and flux) correctors and the homogenization commutator. Both oscillation and fluctuation estimates rely on a sensitivity calculus, i.e. on estimating how sensitively the quantity of interest does depend on an infinitesimal change in the coefficient field, which is fed into the Spectral Gap inequality. In this article, the annealed CZ estimate is the only form in which elliptic regularity theory enters.

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