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arXiv 1602.04057math.PRcs.NAmath.NA
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关于SPDE轨迹的弱误差估计:谱伽辽金离散化

Weak error estimates for trajectories of SPDEs for Spectral Galerkin discretization

University of Warwick(华威大学)

Charles-Edouard Bréhier, Martin Hairer, Andrew M. Stuart

AI总结:

本文研究了由加性空间相关Wiener噪声驱动的随机半线性演化方程,分析了谱伽辽金方法在热方程和阻尼驱动波动方程中的弱误差估计,证明了弱收敛速率是强收敛速率的两倍。

摘要:

我们考虑由加性、空间相关Wiener噪声驱动的随机半线性演化方程,特别研究热方程(解析半群)和阻尼驱动波动方程(有界半群)类型的问题。通过谱伽辽金投影离散这些方程,并研究轨迹概率分布的近似:测试函数是规则的,但依赖于过程在区间[0,T]上的值。我们引入了在SPDE离散化定量弱误差分析中的新方法。弱误差通过确定性函数(Itô映射)来表征,该函数在非线性项被丢弃时找到的随机卷积。利用Itô映射的正则性性质,并特别使用二阶泰勒展开,将谱近似随机卷积的误差转移到感兴趣的弱误差中。我们证明在两种情况下弱收敛速率是强收敛速率的两倍。第一种情况假设协方差算子与半群生成元相交换:弱误差展开中的第一项因独立性而抵消。第二种情况去除相交换假设,并通过分析新的误差项(依赖于交换子)扩展了前一结果。

英文摘要:

We consider stochastic semi-linear evolution equations which are driven by additive, spatially correlated, Wiener noise, and in particular consider problems of heat equation (analytic semigroup) and damped-driven wave equations (bounded semigroup) type. We discretize these equations by means of a spectral Galerkin projection, and we study the approximation of the probability distribution of the trajectories: test functions are regular, but depend on the values of the process on the interval $[0,T]$. We introduce a new approach in the context of quantative weak error analysis for discretization of SPDEs. The weak error is formulated using a deterministic function (Itô map) of the stochastic convolution found when the nonlinear term is dropped. The regularity properties of the Itô map are exploited, and in particular second-order Taylor expansions employed, to transfer the error from spectral approximation of the stochastic convolution into the weak error of interest. We prove that the weak rate of convergence is twice the strong rate of convergence in two situations. First, we assume that the covariance operator commutes with the generator of the semigroup: the first order term in the weak error expansion cancels out thanks to an independence property. Second, we remove the commuting assumption, and extend the previous result, thanks to the analysis of a new error term depending on a commutator.

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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