Differential geometry | Connection (mathematics)
Let Y → X be an affine bundle modelled over a vector bundle Y → X. A connection Γ on Y → X is called the affine connection if it as a section Γ : Y → J1Y of the jet bundle J1Y → Y of Y is an affine bundle morphism over X. In particular, this is an affine connection on the tangent bundle TX of a smooth manifold X. (That is, the connection on an affine bundle is an example of an affine connection; it is not, however, a general definition of an affine connection. These are related but distinct concepts both unfortunately making use of the adjective "affine".) With respect to affine bundle coordinates (xλ, yi) on Y, an affine connection Γ on Y → X is given by the tangent-valued connection form An affine bundle is a fiber bundle with a general affine structure group GA(m, ℝ) of affine transformations of its typical fiber V of dimension m. Therefore, an affine connection is associated to a principal connection. It always exists. For any affine connection Γ : Y → J1Y, the corresponding linear derivative Γ : Y → J1Y of an affine morphism Γ defines a unique linear connection on a vector bundle Y → X. With respect to linear bundle coordinates (xλ, yi) on Y, this connection reads Since every vector bundle is an affine bundle, any linear connection ona vector bundle also is an affine connection. If Y → X is a vector bundle, both an affine connection Γ and an associated linear connection Γ areconnections on the same vector bundle Y → X, and their difference is a basic soldering form on Thus, every affine connection on a vector bundle Y → X is a sum of a linear connection and a basic soldering form on Y → X. Due to the canonical vertical splitting VY = Y × Y, this soldering form is brought into a vector-valued form where ei is a fiber basis for Y. Given an affine connection Γ on a vector bundle Y → X, let R and R be the curvatures of a connection Γ and the associated linear connection Γ, respectively. It is readily observed that R = R + T, where is the torsion of Γ with respect to the basic soldering form σ. In particular, consider the tangent bundle TX of a manifold X coordinated by (xμ, ẋμ). There is the canonical soldering form on TX which coincides with the tautological one-form on X due to the canonical vertical splitting VTX = TX × TX. Given an arbitrary linear connection Γ on TX, the corresponding affine connection on TX is the Cartan connection. The torsion of the Cartan connection A with respect to the soldering form θ coincides with the torsion of a linear connection Γ, and its curvature is a sum R + T of the curvature and the torsion of Γ. (Wikipedia).
Introduction to Fiber Bundles part 1: Definitions
We give the definition of a fiber bundle with fiber F, trivializations and transition maps. This is a really basic stuff that we use a lot. Here are the topics this sets up: *Associated Bundles/Principal Bundles *Reductions of Structure Groups *Steenrod's Theorem *Torsor structure on arith
From playlist Fiber bundles
Tensor Calculus Episode 10 | Is the Affine Connection a Tensor?
In todays video I look at the transformation properties of the affine connection coefficients to see if they transform as tensor components. This series is based off "Tensor Calculus for Physics" by Dwight Neuenschwander which can be found at: https://www.amazon.com/gp/product/1421415658/
From playlist New To Tensors? Start Here
In this video, I define connectedness, which is a very important concept in topology and math in general. Essentially, it means that your space only consists of one piece, whereas disconnected spaces have two or more pieces. I also define the related notion of path-connectedness. Topology
From playlist Topology
Calculus and affine geometry of the magical parabola | Algebraic Calc and dCB curves 3 | Wild Egg
Algebraic Calculus naturally lives in affine geometry, not Euclidean geometry. Affine geometry is the geometry of parallelism, or (almost the same thing) --- the geometry of pure linear algebra. The parabola is characterized projectively in this geometry as the unique conic which is tangen
From playlist Algebraic Calculus One Info
Affine Springer fibers and representation theory - Cheng-Chiang Tsai
Short talk by postdoctoral members Topic: Affine Springer fibers and representation theory Speaker: Cheng-Chiang Tsai, Member, School of Mathematics For more videos, visit http://video.ias.edu
From playlist Mathematics
The TRUTH about TENSORS, Part 9: Vector Bundles
In this video we define vector bundles in full abstraction, of which tangent bundles are a special case.
From playlist The TRUTH about TENSORS
Tensor Calculus For Physics Ep. 11 | The Covariant Derivative
This video shows how to modify the notion of the derivative to include the affine connection, guaranteeing that the (covariant) derivative of a tensor yields another tensor. This series is based off "Tensor Calculus for Physics" by Dwight Neuenschwander which can be found at: https://www.
From playlist New To Tensors? Start Here
What are Connected Graphs? | Graph Theory
What is a connected graph in graph theory? That is the subject of today's math lesson! A connected graph is a graph in which every pair of vertices is connected, which means there exists a path in the graph with those vertices as endpoints. We can think of it this way: if, by traveling acr
From playlist Graph Theory
Holomorphic rigid geometric structures on compact manifolds by Sorin Dumitrescu
Higgs bundles URL: http://www.icts.res.in/program/hb2016 DATES: Monday 21 Mar, 2016 - Friday 01 Apr, 2016 VENUE : Madhava Lecture Hall, ICTS Bangalore DESCRIPTION: Higgs bundles arise as solutions to noncompact analog of the Yang-Mills equation. Hitchin showed that irreducible solutio
From playlist Higgs Bundles
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
Rod Gover - Geometric Compactification, Cartan holonomy, and asymptotics
Conformal compactification has long been recognised as an effective geometric framework for relating conformal geometry, and associated field theories « at infinity », to the asymptotic phenomena of an interior (pseudo‐)‐Riemannian geometry of one higher dimension. It provides an effective
From playlist Ecole d'été 2014 - Analyse asymptotique en relativité générale
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
Even spaces and motivic resolutions - Michael Hopkins
Vladimir Voevodsky Memorial Conference Topic: Even spaces and motivic resolutions Speaker: Michael Hopkins Affiliation: Harvard University Date: September 13, 2018 For more video please visit http://video.ias.edu
From playlist Mathematics
Branimir Cacic, Classical gauge theory on quantum principalbundles
Noncommutative Geometry Seminar (Europe), 20 October 2021
From playlist Global Noncommutative Geometry Seminar (Europe)
Representations of Fuchsian groups, parahoric group schemes by Vikraman Balaji
DISCUSSION MEETING : MODULI OF BUNDLES AND RELATED STRUCTURES ORGANIZERS : Rukmini Dey and Pranav Pandit DATE : 10 February 2020 to 14 February 2020 VENUE : Ramanujan Lecture Hall, ICTS, Bangalore Background: At its core, much of mathematics is concerned with the problem of classif
From playlist Moduli Of Bundles And Related Structures 2020
Isabel Vogt - An enriched count of the bitangents to a smooth plane quartic curve - AGONIZE
Recent work of Kass–Wickelgren gives an enriched count of the 27 lines on a smooth cubic surface over arbitrary fields, generalizing Segre’s signed count count of elliptic and hyperbolic lines. Their approach using 𝔸1-enumerative geometry suggests that other classical enumerative problems
From playlist Arithmetic Geometry is ONline In Zoom, Everyone (AGONIZE)
From Cohomology to Derived Functors by Suresh Nayak
PROGRAM DUALITIES IN TOPOLOGY AND ALGEBRA (ONLINE) ORGANIZERS: Samik Basu (ISI Kolkata, India), Anita Naolekar (ISI Bangalore, India) and Rekha Santhanam (IIT Mumbai, India) DATE & TIME: 01 February 2021 to 13 February 2021 VENUE: Online Duality phenomena are ubiquitous in mathematics
From playlist Dualities in Topology and Algebra (Online)
algebraic geometry 17 Affine and projective varieties
This lecture is part of an online algebraic geometry course, based on chapter I of "Algebraic geometry" by Hartshorne. It covers the relation between affine and projective varieties, with some examples such as a cubic curve and the twisted cubic.
From playlist Algebraic geometry I: Varieties