Homological algebra | Module theory

Projective module

In mathematics, particularly in algebra, the class of projective modules enlarges the class of free modules (that is, modules with basis vectors) over a ring, by keeping some of the main properties of free modules. Various equivalent characterizations of these modules appear below. Every free module is a projective module, but the converse fails to hold over some rings, such as Dedekind rings that are not principal ideal domains. However, every projective module is a free module if the ring is a principal ideal domain such as the integers, or a polynomial ring (this is the Quillen–Suslin theorem). Projective modules were first introduced in 1956 in the influential book Homological Algebra by Henri Cartan and Samuel Eilenberg. (Wikipedia).

Projective module
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Rings 9 Projective modules

This lecture is part of an online course on rings and modules. We define projective modules, and give severalexamples of them, including the Moebius band, a non-principal ideal, and the tangent bundle of the sphere. For the other lectures in the course see https://www.youtube.com/playli

From playlist Rings and modules

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Introduction to Projective Geometry (Part 1)

The first video in a series on projective geometry. We discuss the motivation for studying projective planes, and list the axioms of affine planes.

From playlist Introduction to Projective Geometry

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algebraic geometry 15 Projective space

This lecture is part of an online algebraic geometry course, based on chapter I of "Algebraic geometry" by Hartshorne. It introduces projective space and describes the synthetic and analytic approaches to projective geometry

From playlist Algebraic geometry I: Varieties

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This lecture is part of an online course on commutative algebra, following the book "Commutative algebra with a view toward algebraic geometry" by David Eisenbud. We discuss the relation between locally free things (vector bundles) and projective things. In commutative algebra and differe

From playlist Commutative algebra

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The projective Quadruple quad formula | Rational Geometry Math Foundations 148 | NJ Wildberger

In this video we introduce the projective version of the Quadruple quad formula, which not only controls the relationship between four projective points, but has a surprising connection with the geometry of the cyclic quadrilateral. The projective quadruple quad function is called R(a,b,

From playlist Math Foundations

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A module is a generalization of a vector space. You can think of it as a group of vectors with scalars from a ring instead of a field. In this lesson, we introduce the module, give a variety of examples, and talk about the ways in which modules and vector spaces are different from one an

From playlist Abstract Algebra

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Projective geometry began with the work of Pappus, but was developed primarily by Desargues, with an important contribution by Pascal. Projective geometry is the geometry of the straightedge, and it is the simplest and most fundamental geometry. We describe the important insights of the 19

From playlist MathHistory: A course in the History of Mathematics

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Andy Magid, University of Oklahoma (hybrid talk)

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From playlist Fall 2022 Online Kolchin seminar in Differential Algebra

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Commutative algebra 43 (Stalkwise locally free modules)

This lecture is part of an online course on commutative algebra, following the book "Commutative algebra with a view toward algebraic geometry" by David Eisenbud. We discuss the rather technical concept of stalkwise locally free modules: those such that all localizations at primes are fre

From playlist Commutative algebra

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Broué’s Abelian Defect Group Conjecture I - Jay Taylor

Seminar on Geometric and Modular Representation Theory Topic: Broué’s Abelian Defect Group Conjecture I Speaker: Jay Taylor Affiliation: University of Southern California; Member, School of Mathematics Date: September 9, 2020 For more video please visit http://video.ias.edu

From playlist Seminar on Geometric and Modular Representation Theory

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Broué’s Abelian Defect Group Conjecture II - Daniel Juteau

Seminar on Geometric and Modular Representation Theory Topic: Broué’s Abelian Defect Group Conjecture II Speaker: Daniel Juteau Affiliation: Centre National de la Recherche Scientifique/Université Paris Diderot; Member, School of Mathematics Date: September 16, 2020 For more video please

From playlist Seminar on Geometric and Modular Representation Theory

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Dave Benson: Spectral methods in the representation theory of finite groups - Lecture 2

My intention is to develop the cohomology theory of finite groups and use it to discuss the stable module category and the homotopy category of complexes of injective modules, and to relate them to the modules over cochains on the classifying space. This video is part of a series of lectu

From playlist Summer School: Spectral methods in algebra, geometry, and topology

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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

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MountainWest JavaScript 2014 - Browser Package Management by Guy Bedford

We still don't have a sensible package management workflow for the browser. Instead we have various pieces of package management tooling that may or may not play well together. The main reason for this is the lack of agreement on a module system and module loader for the browser. With the

From playlist MountainWest JavaScript 2014

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