In mathematics, in algebra, in the realm of group theory, a subgroup of a finite group is said to be semipermutable if commutes with every subgroup whose order is relatively prime to that of . Clearly, every permutable subgroup of a finite group is semipermutable. The converse, however, is not necessarily true. (Wikipedia).
Inner & Outer Semidirect Products Derivation - Group Theory
Semidirect products are a very important tool for studying groups because they allow us to break a group into smaller components using normal subgroups and complements! Here we describe a derivation for the idea of semidirect products and an explanation of how the map into the automorphism
From playlist Group Theory
Walter van Suijlekom: Semigroup of inner perturbations in Non Commutative Geometry
Starting with an algebra, we define a semigroup which extends the group of invertible elements in that algebra. As we will explain, this semigroup describes inner perturbations of noncommutative manifolds, and has applications to gauge theories in physics. We will present some elementary e
From playlist HIM Lectures: Trimester Program "Non-commutative Geometry and its Applications"
Group theory 7: Semidirect products
This is lecture 7 of an online course on group theory. It covers semidirect products and uses them to classify groups of order 6.
From playlist Group theory
Semi-coarse Spaces, Homotopy [Jonathan Treviño-Marroquín]
Semi-coarse spaces is an alternative to study (undirected) graphs through large-scale geometry. In this video, we present the structure and a homotopy what we worked on. In the final part, we look at the fundamental homotopy group of cyclic graphs.
From playlist Contributed Videos
Before we carry on with our coset journey, we need to discover when the left- and right cosets are equal to each other. The obvious situation is when our group is Abelian. The other situation is when the subgroup is a normal subgroup. In this video I show you what a normal subgroup is a
From playlist Abstract algebra
Abstract Algebra | Cyclic Subgroups
We define the notion of a cyclic subgroup and give a few examples. http://www.michael-penn.net http://www.randolphcollege.edu/mathematics/
From playlist Abstract Algebra
In this tutorial we define a subgroup and prove two theorem that help us identify a subgroup. These proofs are simple to understand. There are also two examples of subgroups.
From playlist Abstract algebra
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
(ML 19.5) Positive semidefinite kernels (Covariance functions)
Definition of a positive semidefinite kernel, or covariance function. A simple example. Explanation of terminology: autocovariance, positive definite kernel, stationary kernel, isotropic kernel, covariogram, positive definite function.
From playlist Machine Learning
Lie Groups and Lie Algebras: Lesson 43 Group Theory Review #2 (improved video quality)
Lie Groups and Lie Algebras: Lesson 43 Group Theory Review #2 In this lecture we examine a great way of becoming familiar with the smaller groups: the subgroup lattice. We use this to remind ourselves about normal subgroups, cyclic subgroups, and the center of a group. Errata!: The norma
From playlist Lie Groups and Lie Algebras
Cyclic Groups -- Abstract Algebra 7
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From playlist Abstract Algebra
Lie Groups and Lie Algebras: Lesson 44 Group Theory Review #3 (corrected!)
Lie Groups and Lie Algebras: Lesson 44 Group Theory Review #3 This is a corrected version of a previous upload. In the earlier version I ridiculously stated that cyclic subgroups were normal. I don't know what came over me, that is certainly NOT true. What is true is that if a group is a
From playlist Lie Groups and Lie Algebras
Lagrange's Theorem and Index of Subgroups | Abstract Algebra
We introduce Lagrange's theorem, showing why it is true and follows from previously proven results about cosets. We also investigate groups of prime order, seeing how Lagrange's theorem informs us about every group of prime order - in particular it tells us that any group of prime order p
From playlist Abstract Algebra
Visual Group Theory, Lecture 4.5: The isomorphism theorems
Visual Group Theory, Lecture 4.5: The isomorphism theorems There are four central results in group theory that are collectively known at the isomorphism theorems. We introduced the first of these a few lectures back, under the name of the "fundamental homomorphism theorem." In this lectur
From playlist Visual Group Theory
Visual Group Theory, Lecture 5.3: Examples of group actions
Visual Group Theory, Lecture 5.3: Examples of group actions It is frequently of interest to analyze the action of a group on its elements (by multiplication), subgroups (by multiplication, or by conjugation), or cosets (by multiplication). We look at all of these, and analyze the orbits,
From playlist Visual Group Theory
Group theory 15:Groups of order 12
This lecture is part of an online mathematics course on group theory. It uses the Sylow theorems to classify the groups of order 12, and finds their subgroups.
From playlist Group theory
No simple groups of order 66 or 144.
We look at an "advanced" group theory problem that uses Sylow's Theorems to show that there are no simple groups of order 66 or 144. Suggest a problem: https://forms.gle/ea7Pw7HcKePGB4my5 Please Subscribe: https://www.youtube.com/michaelpennmath?sub_confirmation=1 Merch: https://teespri
From playlist Assorted Group Theory
Why Normal Subgroups are Necessary for Quotient Groups
Proof that cosets are disjoint: https://youtu.be/uxhAUmgSHnI In order for a subgroup to create a quotient group (also known as factor group), it must be a normal subgroup. That means that when we conjugate an element in the subgroup, it stays in the subgroup. In this video, we explain wh
From playlist Group Theory
Visual Group Theory, Lecture 3.1: Subgroups
Visual Group Theory, Lecture 3.1: Subgroups In this lecture, we begin by examining a property about Cayley graphs called "regularity" that we've hinted at but not yet spelled out explicitly. Next, we introduce the concept of a subgroup, provide some examples, and show how the subgroups of
From playlist Visual Group Theory
EDIT: At 6:24, the product should be "(e sub H, e sub N)", not "(e sub H, e sub G)" Abstract Algebra: Using automorphisms, we define the semidirect product of two groups. We prove the group property and construct various examples, including the dihedral groups. As an application, we
From playlist Abstract Algebra