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通过接触镜看欧拉流:普遍性和图灵完备性

Looking at Euler flows through a contact mirror: Universality and Turing completeness
课程网址: http://videolectures.net/8ecm2021_miranda_loking_euler/  
主讲教师: Eva Miranda
开课单位: 巴黎狄德罗大学
开课时间: 2021-07-06
课程语种: 英语
中文简介:
黎曼流形上无粘性和不可压缩流体流动的动力学由欧拉方程控制。最近,Tao [6, 7, 8] 启动了一个程序来解决基于普遍性概念的 Euler 和 Navier-Stokes 方程的全局存在性问题。受此提议的启发,我们证明了平稳欧拉方程表现出几个普遍性特征,从某种意义上说,紧凑流形上的任何非自治流都可以扩展到某个可能更高的黎曼流形上的欧拉方程的平滑平稳解维度 [1]。证明中的一个关键点是通过接触镜观察接触几何中的 h 原理,该原理由 Etnyre 和 Ghrist 在 20 多年前的 [4] 中揭示。我们结束了这个演讲,解决了 Moore 在 [5] 中提出的一个问题:“流体动力学是否能够执行计算?”。上面的普遍性结果产生了 17 维球面上的稳定欧拉流的图灵完备性。这个结果可以改进吗?在 [2] 中,我们在维度 3 中构造了一个图灵完备的欧拉流。如果时间允许,我们将讨论这个和 [3] 中包含的其他概括。本次演讲基于与 Cardona、Peralta-Salas 和 Presas 的几项联合工作。
课程简介: The dynamics of an inviscid and incompressible fluid flow on a Riemannian manifold is governed by the Euler equations. Recently, Tao [6, 7, 8] launched a programme to address the global existence problem for the Euler and Navier-Stokes equations based on the concept of universality. Inspired by this proposal, we show that the stationary Euler equations exhibit several universality features, in the sense that, any non-autonomous flow on a compact manifold can be extended to a smooth stationary solution of the Euler equations on some Riemannian manifold of possibly higher dimension [1]. A key point in the proof is looking at the h-principle in contact geometry through a contact mirror, unveiled by Etnyre and Ghrist in [4] more than two decades ago. We end up this talk addressing a question raised by Moore in [5] : “Is hydrodynamics capable of performing computations?”. The universality result above yields the Turing completeness of the steady Euler flows on a 17- dimensional sphere. Can this result be improved? In [2] we construct a Turing complete Euler flow in dimension 3. Time permitting, we discuss this and other generalizations contained in [3]. This talk is based on several joint works with Cardona, Peralta-Salas and Presas.
关 键 词: 黎曼流形; 欧拉方程; 图灵完备性
课程来源: 视频讲座网
数据采集: 2022-03-24:hqh
最后编审: 2022-03-25:liyy
阅读次数: 28