Riemannian manifolds

Flat manifold

In mathematics, a Riemannian manifold is said to be flat if its Riemann curvature tensor is everywhere zero. Intuitively, a flat manifold is one that "locally looks like" Euclidean space in terms of distances and angles, e.g. the interior angles of a triangle add up to 180°. The universal cover of a complete flat manifold is Euclidean space. This can be used to prove the theorem of Bieberbach that all compact flat manifolds are finitely covered by tori; the 3-dimensional case was proved earlier by . (Wikipedia).

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What is a Manifold? Lesson 6: Topological Manifolds

Topological manifolds! Finally! I had two false starts with this lesson, but now it is fine, I think.

From playlist What is a Manifold?

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Manifolds #5: Tangent Space (part 1)

Today, we introduce the notion of tangent vectors and the tangent vector space at a point on a manifold.

From playlist Manifolds

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What is a manifold?

I define topological manifolds. Motivated by the prospect of calculus on topological manifolds, I introduce smooth manifolds. At the end I point out how one needs to change the definitions, to obtain C^1 or even complex manifolds. To learn more about manifolds, see Lee's "Introduction to

From playlist Differential geometry

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What is a Manifold? Lesson 2: Elementary Definitions

This lesson covers the basic definitions used in topology to describe subsets of topological spaces.

From playlist What is a Manifold?

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Manifolds #2: Charts

Today, we take a look at charts, their transition maps, and coordinate functions.

From playlist Manifolds

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Manifolds 1.1 : Basic Definitions

In this video, I give the basic intuition and definitions of manifolds. Email : fematikaqna@gmail.com Code : https://github.com/Fematika/Animations Notes : None yet

From playlist Manifolds

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Manifolds 1.3 : More Examples (Animation Included)

In this video, I introduce the manifolds of product manifolds, tori/the torus, real vectorspaces, matrices, and linear map spaces. This video uses a math animation for visualization. Email : fematikaqna@gmail.com Code : https://github.com/Fematika/Animations Notes : http://docdro.id/5koj5

From playlist Manifolds

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What is a Manifold? Lesson 3: Separation

He we present some alternative topologies of a line interval and then discuss the notion of separability. Note the error at 4:05. Sorry! If you are viewing this on a mobile device, my annotations are not visible. This is due to a quirck of YouTube.

From playlist What is a Manifold?

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Hao Xu (7/26/22): Frobenius algebra structure of statistical manifold

Abstract: In information geometry, a statistical manifold is a Riemannian manifold (M,g) equipped with a totally symmetric (0,3)-tensor. We show that the tangent bundle of a statistical manifold has a Frobenius algebra structure if and only if the sectional K-curvature vanishes. This gives

From playlist Applied Geometry for Data Sciences 2022

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R. Perales - Recent Intrinsic Flat Convergence Theorems

Given a closed and oriented manifold M and Riemannian tensors g0, g1, ... on M that satisfy g0 gj, vol(M, gj)→vol (M, g0) and diam(M, gj)≤D we will see that (M, gj) converges to (M, g0) in the intrinsic flat sense. We also generalize this to the non-empty bundary setting. We remark that u

From playlist Ecole d'été 2021 - Curvature Constraints and Spaces of Metrics

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R. Perales - Recent Intrinsic Flat Convergence Theorems (version temporaire)

Given a closed and oriented manifold M and Riemannian tensors g0, g1, ... on M that satisfy g0 gj, vol(M, gj)→vol (M, g0) and diam(M, gj)≤D we will see that (M, gj) converges to (M, g0) in the intrinsic flat sense. We also generalize this to the non-empty bundary setting. We remark that u

From playlist Ecole d'été 2021 - Curvature Constraints and Spaces of Metrics

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Holomorphic Cartan geometries on simply connected manifolds by Sorin Dumitrescu

Discussion Meeting Complex Algebraic Geometry ORGANIZERS: Indranil Biswas, Mahan Mj and A. J. Parameswaran DATE:01 October 2018 to 06 October 2018 VENUE: Madhava Lecture Hall, ICTS, Bangalore The discussion meeting on Complex Algebraic Geometry will be centered around the "Infosys-ICT

From playlist Complex Algebraic Geometry 2018

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Jintian Zhu - Incompressible hypersurface, positive scalar curvature and positive mass theorem

In this talk, I will introduce a positive mass theorem for asymptotically flat manifolds with fibers (like ALF and ALG manifolds) under an additional but necessary incompressible condition. I will also make a discussion on its connection with surgery theory as well as quasi-local mass and

From playlist Not Only Scalar Curvature Seminar

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A. Song - What is the (essential) minimal volume? 2 (version temporaire)

I will discuss the notion of minimal volume and some of its variants. The minimal volume of a manifold is defined as the infimum of the volume over all metrics with sectional curvature between -1 and 1. Such an invariant is closely related to "collapsing theory", a far reaching set of resu

From playlist Ecole d'été 2021 - Curvature Constraints and Spaces of Metrics

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A. Song - What is the (essential) minimal volume? 2

I will discuss the notion of minimal volume and some of its variants. The minimal volume of a manifold is defined as the infimum of the volume over all metrics with sectional curvature between -1 and 1. Such an invariant is closely related to "collapsing theory", a far reaching set of resu

From playlist Ecole d'été 2021 - Curvature Constraints and Spaces of Metrics

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Christina Sormani: A Course on Intrinsic Flat Convergence part 1

Intrinsic Flat Convergence was first introduced in joint work with Stefan Wenger building upon work of Ambrosio-Kirchheim to address a question proposed by Tom Ilmanen. In this talk, I will present an overview of the initial paper on the topic [JDG 2011]. I will briefly describe key examp

From playlist HIM Lectures 2015

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Branched Holomorphic Cartan Geometries by Sorin Dumitrescu

DISCUSSION MEETING ANALYTIC AND ALGEBRAIC GEOMETRY DATE:19 March 2018 to 24 March 2018 VENUE:Madhava Lecture Hall, ICTS, Bangalore. Complex analytic geometry is a very broad area of mathematics straddling differential geometry, algebraic geometry and analysis. Much of the interactions be

From playlist Analytic and Algebraic Geometry-2018

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What is a Manifold? Lesson 4: Countability and Continuity

In this lesson we review the idea of first and second countability. Also, we study the topological definition of a continuous function and then define a homeomorphism.

From playlist What is a Manifold?

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Colloquium MathAlp 2019 - Claude Lebrun

Claude Lebrun - Mass, Scalar Curvature, Kähler Geometry, and All That Given a complete Riemannian manifold that looks enough like Euclidean space at infinity, physicists have defined a quantity called the “mass” that measures the asymptotic deviation of the geometry from the Euclidean mod

From playlist Colloquiums MathAlp

Related pages

Conformally flat manifold | Sectional curvature | Orbifold | Space form | Ricci-flat manifold | Bass–Serre theory | Möbius strip | Klein bottle | Symmetric space | Space group | Riemann curvature tensor | Glide plane | Quotient group | Hadamard space | Affine manifold | Building (mathematics) | Mathematics | Cube | Riemannian manifold | Hexagonal prism | Euclidean space | Amenable group | 3-torus | Hantzsche–Wendt manifold | Compact space | Fundamental group | Seifert fiber space