Differential geometry | Conformal geometry | Incidence geometry
Lie sphere geometry is a geometrical theory of planar or spatial geometry in which the fundamental concept is the circle or sphere. It was introduced by Sophus Lie in the nineteenth century. The main idea which leads to Lie sphere geometry is that lines (or planes) should be regarded as circles (or spheres) of infinite radius and that points in the plane (or space) should be regarded as circles (or spheres) of zero radius. The space of circles in the plane (or spheres in space), including points and lines (or planes) turns out to be a manifold known as the Lie quadric (a quadric hypersurface in projective space). Lie sphere geometry is the geometry of the Lie quadric and the Lie transformations which preserve it. This geometry can be difficult to visualize because Lie transformations do not preserve points in general: points can be transformed into circles (or spheres). To handle this, curves in the plane and surfaces in space are studied using their contact lifts, which are determined by their tangent spaces. This provides a natural realisation of the osculating circle to a curve, and the of a surface. It also allows for a natural treatment of Dupin cyclides and a conceptual solution of the problem of Apollonius. Lie sphere geometry can be defined in any dimension, but the case of the plane and 3-dimensional space are the most important. In the latter case, Lie noticed a remarkable similarity between the Lie quadric of spheres in 3-dimensions, and the space of lines in 3-dimensional projective space, which is also a quadric hypersurface in a 5-dimensional projective space, called the PlĂĽcker or Klein quadric. This similarity led Lie to his famous "line-sphere correspondence" between the space of lines and the space of spheres in 3-dimensional space. (Wikipedia).
Lie derivatives of differential forms
Introduces the lie derivative, and its action on differential forms. This is applied to symplectic geometry, with proof that the lie derivative of the symplectic form along a Hamiltonian vector field is zero. This is really an application of the wonderfully named "Cartan's magic formula"
From playlist Symplectic geometry and mechanics
From playlist Drawing a sphere
This lecture is part of an online graduate course on Lie groups. We define the Lie algebra of a Lie group in two ways, and show that it satisfied the Jacobi identity. The we calculate the Lie algebras of a few Lie groups. For the other lectures in the course see https://www.youtube.co
From playlist Lie groups
Learn how to determine the volume of a sphere
👉 Learn how to find the volume and the surface area of a sphere. A sphere is a perfectly round 3-dimensional object. It is an object with the shape of a round ball. The distance from the center of a sphere to any point on its surface is called the radius of the sphere. A sphere has a unifo
From playlist Volume and Surface Area
Finding the volume and the surface area of a sphere
👉 Learn how to find the volume and the surface area of a sphere. A sphere is a perfectly round 3-dimensional object. It is an object with the shape of a round ball. The distance from the center of a sphere to any point on its surface is called the radius of the sphere. A sphere has a unifo
From playlist Volume and Surface Area
Find the volume of a sphere given the circumference
👉 Learn how to find the volume and the surface area of a sphere. A sphere is a perfectly round 3-dimensional object. It is an object with the shape of a round ball. The distance from the center of a sphere to any point on its surface is called the radius of the sphere. A sphere has a unifo
From playlist Volume and Surface Area
Lie groups: Lie groups and Lie algebras
This lecture is part of an online graduate course on Lie groups. We discuss the relation between Lie groups and Lie algebras, and give several examples showing how they behave differently. Lie algebras turn out to correspond more closely to the simply connected Lie groups. We then explain
From playlist Lie groups
How do you find the surface area of a sphere
👉 Learn how to find the volume and the surface area of a sphere. A sphere is a perfectly round 3-dimensional object. It is an object with the shape of a round ball. The distance from the center of a sphere to any point on its surface is called the radius of the sphere. A sphere has a unifo
From playlist Volume and Surface Area
Introduction to Projective Geometry (Part 2)
The second video in a series about projective geometry. We list the axioms for projective planes, give an examle of a projective plane with finitely many points, and define the real projective plane.
From playlist Introduction to Projective Geometry
Probability With Geometry - Length, Area & Volume
This geometry video tutorial provides a basic introduction into probability. It's a nice review that explains how to calculate the probability given the length of a segment, the area of triangles and rectangles or the volume of a sphere within a cube. This video contains plenty of exampl
From playlist Geometry Video Playlist
A problem in Elementary Geometry - Michael Atiyah [2011]
Name: Michael Atiyah Event: SCGP Weekly Talk Title: A problem in Elementary Euclidean Geometry Date: 2011-10-25 @1:00 PM Location: 103 Abstract: Over a decade ago I stumbled across a new and apparently very elementary problem in Euclidean Geometry involving n distinct points in 3-space. E
From playlist Mathematics
GAME2020 2. Hugo Hadfield, Eric Wieser. Robots, Ganja & Screw Theory (new audio!)
(* this version has an updated filtered audio track *) Hugo Hadfield and Eric Wieser explore how Conformal Geometric Algebra can be used to simplify robot kinematics. (slides : https://slides.com/hugohadfield/game2020). More information at https://bivector.net Chapters: 0:00 Introduction
From playlist Bivector.net
Robert Bryant, A visit to the Finsler worldÂ
Robert Bryant, Duke University, USA A visit to the Finsler worldÂ
From playlist Conférence en l'honneur de Jean-Pierre Bourguignon
Fitting manifolds to data - Charlie Fefferman
Workshop on Topology: Identifying Order in Complex Systems Topic: Fitting manifolds to data Speaker: Charlie Fefferman Affiliation: Princeton University Date: April 7, 2018 For more videos, please visit http://video.ias.edu
From playlist Mathematics
This lecture is part of an online graduate course on Lie groups. We give an introductory survey of Lie groups theory by describing some examples of Lie groups in low dimensions. Some recommended books: Lie algebras and Lie groups by Serre (anything by Serre is well worth reading) Repre
From playlist Lie groups
Perspectives in Math and Art by Supurna Sinha
KAAPI WITH KURIOSITY PERSPECTIVES IN MATH AND ART SPEAKER: Supurna Sinha (Raman Research Institute, Bengaluru) WHEN: 4:00 pm to 5:30 pm Sunday, 24 April 2022 WHERE: Jawaharlal Nehru Planetarium, Bengaluru Abstract: The European renaissance saw the merging of mathematics and art in th
From playlist Kaapi With Kuriosity (A Monthly Public Lecture Series)
Minimum Bounding Circles and Spheres | galproject
This video covers an algorithm to compute the minimum bounding circles and spheres. The source code: https://github.com/ranjeethmahankali/galproject Computational Geometry Algorithms and Applications (book): https://link.springer.com/book/10.1007/978-3-540-77974-2 https://www.amazon.com/
From playlist Summer of Math Exposition Youtube Videos
Jessica Purcell - Lecture 2 - Fully augmented links and circle packings
Jessica Purcell, Monash University Title: Fully augmented links and circle packings Fully augmented links form a family of hyperbolic links that are a playground for hands-on hyperbolic geometry. In the first part of the talk, I’ll define the links and show how to determine their hyperboli
From playlist 39th Annual Geometric Topology Workshop (Online), June 6-8, 2022