Categories in category theory | Group theory

Category of abelian groups

In mathematics, the category Ab has the abelian groups as objects and group homomorphisms as morphisms. This is the prototype of an abelian category: indeed, every small abelian category can be embedded in Ab. (Wikipedia).

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Groups and subgroups

Jacob explains the fundamental concepts in group theory of what groups and subgroups are, and highlights a few examples of groups you may already know. Abelian groups are named in honor of Niels Henrik Abel (https://en.wikipedia.org/wiki/Niels_Henrik_Abel), who pioneered the subject of

From playlist Basics: Group Theory

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Group theory 31: Free groups

This lecture is part of an online math course on group theory. We review free abelian groups, then construct free (non-abelian) groups, and show that they are given by the set of reduced words, and as a bonus find that they are residually finite.

From playlist Group theory

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Group theory 17: Finite abelian groups

This lecture is part of a mathematics course on group theory. It shows that every finitely generated abelian group is a sum of cyclic groups. Correction: At 9:22 the generators should be g, h+ng not g, g+nh

From playlist Group theory

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Derived Categories part 1

We give a buttload of definitions for morphisms on various categories of complexes. The derived category of an abelian category is a category whose objects are cochain complexes and whose morphisms I describe in this video.

From playlist Derived Categories

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Every Group of Order Five or Smaller is Abelian Proof

Please Subscribe here, thank you!!! https://goo.gl/JQ8Nys Every Group of Order Five or Smaller is Abelian Proof. In this video we prove that if G is a group whose order is five or smaller, then G must be abelian.

From playlist Abstract Algebra

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Visual Group Theory, Lecture 2.1: Cyclic and abelian groups

Visual Group Theory, Lecture 2.1: Cyclic and abelian groups In this lecture, we introduce two important families of groups: (1) "cyclic groups", which are those that can be generated by a single element, and (2) "abelian groups", which are those for which multiplication commutes. Addition

From playlist Visual Group Theory

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Visual Group Theory, Lecture 4.4: Finitely generated abelian groups

Visual Group Theory, Lecture 4.4: Finitely generated abelian groups We begin this lecture by proving that the cyclic group of order n*m is isomorphic to the direct product of cyclic groups of order n and m if and only if gcd(n,m)=1. Then, we classify all finite abelian groups by decomposi

From playlist Visual Group Theory

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AlgTopReview4: Free abelian groups and non-commutative groups

Free abelian groups play an important role in algebraic topology. These are groups modelled on the additive group of integers Z, and their theory is analogous to the theory of vector spaces. We state the Fundamental Theorem of Finitely Generated Commutative Groups, which says that any such

From playlist Algebraic Topology

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Definition of a group Lesson 24

In this video we take our first look at the definition of a group. It is basically a set of elements and the operation defined on them. If this set of elements and the operation defined on them obey the properties of closure and associativity, and if one of the elements is the identity el

From playlist Abstract algebra

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Lecture 1: Invitation to topos theory

This talk introduces the motivating question for this semester of the Curry-Howard seminar, which is how to organise mathematical knowledge using topoi. The approach sketched out in the talk is via first-order theories, their associated classifying topoi, and adjoint pairs of functors betw

From playlist Topos theory seminar

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Lie Algebras and Homotopy Theory - Jacob Lurie

Members' Seminar Topic: Lie Algebras and Homotopy Theory Speaker: Jacob Lurie Affiliation: Professor, School of Mathematics Date: November 11, 2019 For more video please visit http://video.ias.edu

From playlist Mathematics

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Categories 2: Functors

This lecture is part of an online course on category theory. We define functors and give some examples of them. For the other lectures in the course see https://www.youtube.com/playlist?list=PL8yHsr3EFj51F9XZ_Ka4bLnQoxTdMx0AL

From playlist Categories for the idle mathematician

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Sucharit Sarkar - Khovanov homotopy type

June 29, 2018 - This talk was part of the 2018 RTG mini-conference Low-dimensional topology and its interactions with symplectic geometry

From playlist 2018 RTG mini-conference on low-dimensional topology and its interactions with symplectic geometry II

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Lecture 6: HKR and the cotangent complex

In this video, we discuss the cotangent complex and give a proof of the HKR theorem (in its affine version) Feel free to post comments and questions at our public forum at https://www.uni-muenster.de/TopologyQA/index.php?qa=tc-lecture Homepage with further information: https://www.uni-m

From playlist Topological Cyclic Homology

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The rising sea: Grothendieck on simplicity and generality - Colin McLarty [2003]

Slides for this talk: https://drive.google.com/file/d/1yDmqhdcKo6-YpDpRdHh2hvuNirZVbcKr/view?usp=sharing Notes for this talk: https://drive.google.com/open?id=1p45B3Hh8WPRhdhQAd0Wq0MvmY0JYSnmc The History of Algebra in the Nineteenth and Twentieth Centuries April 21 - 25, 2003 Colin Mc

From playlist Mathematics

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Stefano Marseglia, Computing isomorphism classes of abelian varieties over finite fields

VaNTAGe Seminar, February 1, 2022 License: CC-BY-NC-SA Links to some of the papers mentioned in this talk: Honda: https://doi.org/10.2969/jmsj/02010083 Tate: https://link.springer.com/article/10.1007/BF01404549 Deligne: https://eudml.org/doc/141987 Hofmann, Sircana: https://arxiv.org/ab

From playlist Curves and abelian varieties over finite fields

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Marc Levine - "The Motivic Fundamental Group"

Research lecture at the Worldwide Center of Mathematics.

From playlist Center of Math Research: the Worldwide Lecture Seminar Series

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Lecture 12: Classifying topoi (Part 1)

This is the first of several talks on the subject of classifying topoi. I began with a brief reminder of the overall picture from the first talk, i.e. what are classifying topoi and why do we care (from the point of view of organising mathematics). Then I spent some time talking about tens

From playlist Topos theory seminar

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GT2. Definition of Subgroup

Abstract Algebra: We define the notion of a subgroup and provide various examples. We also consider cyclic subgroups and subgroups generated by subsets in a given group G. Example include A4 and D8. U.Reddit course materials available at http://ureddit.com/class/23794/intro-to-group-

From playlist Abstract Algebra

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Topos seminar Lecture 15: Abstraction and adjunction (Part 1)

I begin by explaining in a simple example the connection between formal reasoning involving distinct concepts, and adjunctions between classifying topoi. This leads to a discussion of models in topoi (focused on the particular example of the theory of abelian groups) then to the syntactic

From playlist Topos theory seminar

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Complete category | Category of sets | Category of modules | Injective module | Tensor product | Divisible group | Coproduct | Isomorphism | Injective cogenerator | Forgetful functor | Trivial group | Additive category | Topos | Preadditive category | Categories for the Working Mathematician | Product (category theory) | Quotient group | Direct limit | Direct product of groups | Projective module | Adjoint functors | Kernel (category theory) | Abelian category | Closed monoidal category | Cokernel | Free abelian group | Function (mathematics) | Mathematics | Set (mathematics) | Biproduct | Normal subgroup | Cartesian product | Category theory | Morphism | Concrete category | Monomorphism | Group homomorphism | Category of groups | Epimorphism | Monoidal category | Kernel (algebra) | Generator (category theory) | Abelian group | Grothendieck category | Exact functor