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arXiv 1705.05554math.NAcs.NA
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利用投影多项式在矩阵流形上构造高阶反向映射

High-Order Retractions on Matrix Manifolds using Projected Polynomials

University of California, San Diego(加州大学圣地亚哥分校)

Evan S. Gawlik, Melvin Leok

AI总结:

本文基于Bessel多项式提出高阶结构保持的Riemannian指数映射近似方法,应用于单位ary矩阵、Grassmann流形和Stiefel流形,同时研究了酉矩阵几何与算术平均的超接近性。

摘要:

我们推导出一系列高阶、保持结构的Riemannian指数映射近似方法,应用于若干矩阵流形,包括单位ary矩阵群、Grassmann流形和Stiefel流形。我们的推导灵感来源于观察到若Ω为斜Hermitian矩阵且t为足够小的标量,则存在一个以tΩ为变量的n次多项式(即Bessel多项式),其极分解可提供e^{tΩ}的近似,误差为O(t^{2n+1})。我们证明了这一事实,并利用它推导出Grassmann和Stiefel流形上的高阶Riemannian指数映射近似。在此过程中,我们还推导了关于酉矩阵几何平均和算术平均超接近性的相关结果。

英文摘要:

We derive a family of high-order, structure-preserving approximations of the Riemannian exponential map on several matrix manifolds, including the group of unitary matrices, the Grassmannian manifold, and the Stiefel manifold. Our derivation is inspired by the observation that if $Ω$ is a skew-Hermitian matrix and $t$ is a sufficiently small scalar, then there exists a polynomial of degree $n$ in $tΩ$ (namely, a Bessel polynomial) whose polar decomposition delivers an approximation of $e^{tΩ}$ with error $O(t^{2n+1})$. We prove this fact and then leverage it to derive high-order approximations of the Riemannian exponential map on the Grassmannian and Stiefel manifolds. Along the way, we derive related results concerning the supercloseness of the geometric and arithmetic means of unitary matrices.

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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