In algebra, the fixed-point subgroup of an automorphism f of a group G is the subgroup of G: More generally, if S is a set of automorphisms of G (i.e., a subset of the automorphism group of G), then the set of the elements of G that are left fixed by every automorphism in S is a subgroup of G, denoted by GS. For example, take G to be the group of invertible n-by-n real matrices and (called the Cartan involution). Then is the group of n-by-n orthogonal matrices. To give an abstract example, let S be a subset of a group G. Then each element s of S can be associated with the automorphism , i.e. conjugation by s. Then ; that is, the centralizer of S. (Wikipedia).
Group Theory: The Center of a Group G is a Subgroup of G Proof
Please Subscribe here, thank you!!! https://goo.gl/JQ8Nys Group Theory: The Center of a Group G is a Subgroup of G Proof
From playlist Abstract Algebra
Visual Group Theory, Lecture 5.4: Fixed points and Cauchy's theorem
Visual Group Theory, Lecture 5.4: Fixed points and Cauchy's theorem We begin with a small lemma stating that if a group of prime order acts on a set S, then the number of fixed points is congruent to the size of the set, modulo p. We need this result to prove Cauchy's theorem, which says
From playlist Visual Group Theory
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
Difference Between Normalizer, Centralizer, and Stabilizer
An easy way to remember what is the normalizer and centralizer of a subgroup, and what is the stabilizer of an element under a group action. For people learning abstract algebra! Group Theory playlist: https://youtube.com/playlist?list=PLug5ZIRrShJHDvvls4OtoBHi6cNnTZ6a6 Subscribe to see
From playlist Group Theory
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
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
Abstract Algebra | Normal Subgroups
We give the definition of a normal subgroup and give some examples. http://www.michael-penn.net http://www.randolphcollege.edu/mathematics/
From playlist Abstract Algebra
The idea of a quotient group follows easily from cosets and Lagrange's theorem. In this video, we start with a normal subgroup and develop the idea of a quotient group, by viewing each coset (together with the normal subgroup) as individual mathematical objects in a set. This set, under
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
Monica Nevins: Representations of p-adic groups via their restrictions to compact open subgroups
SMRI Algebra and Geometry Online 'Characters and types: the personality of a representation of a p-adic group, revealed by branching to its compact open subgroups' Monica Nevins (University of Ottawa) Abstract: The theory of complex representations of p-adic groups can feel very technical
From playlist SMRI Algebra and Geometry Online
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
Matthew Conder: Discrete two-generator subgroups of PSL(2,Q_p)
Matthew Conder, University of Auckland Thursday 10 October 2022 Abstract: Discrete two-generator subgroups of PSL(2,R) have been extensively studied by investigating their action by Möbius transformations on the hyperbolic plane. Due to work of Gilman, Rosenberger, Purzitsky and many othe
From playlist SMRI Seminars
Representation theory: Frobenius groups
We recall the definition of a Frobenius group as a transitive permutation group such that any element fixing two points is the identity. Then we prove Frobenius's theorem that the identity together with the elements fixing no points is a normal subgroup. The proof uses induced representati
From playlist Representation theory
Katrin Tent: Sharply 2-transitive groups
Katrin Tent: Sharply 2-transitive groups Abstract Finite sharply 2-transitive groups were classified by Zassenhaus in the 1930s and were shown to have regular abelian normal subgroups. While there were partial results in the infinite setting the question whether the same holds for infini
From playlist Talks of Mathematics Münster's reseachers
Justin Lynd: Control of fixed points and centric linking systems
The lecture was held within the framework of the (Junior) Hausdorff Trimester Program Topology: Workshop "Fusion systems and equivariant algebraic topology"
From playlist HIM Lectures: Junior Trimester Program "Topology"
Group theory 4: Lagrange's theorem
This is lecture 4 of an online course on mathematical group theory. It introduces Lagrange's theorem that the order of a subgroup divides the order of a group, and uses it to show that all groups of prime order are cyclic, and to prove Fermat's theorem and Euler's theorem.
From playlist Group theory
CTNT 2022 - An Introduction to Galois Representations (Lecture 1) - by Alvaro Lozano-Robledo
This video is part of a mini-course on "An Introduction to Galois Representations" that was taught during CTNT 2022, the Connecticut Summer School and Conference in Number Theory. More about CTNT: https://ctnt-summer.math.uconn.edu/
From playlist CTNT 2022 - An Introduction to Galois Representations (by Alvaro Lozano-Robledo)
Group theory 27: The icosahedral group
This lecture is part of an online math course on group theory. The lecture is about a few examples of groups, in particular the icosahedral group. In it we see that the icosahedral group is the only simple group of order 60, and show that all larger alternating groups are simple.
From playlist Group theory
Group theory 32: Subgroups of free groups
This lecture is part of an online mathematics course on group theory. We describe subgroups of free groups, show that they are free, calculate the number of generators, and give two examples.
From playlist Group theory
Definition of a Subgroup in Abstract Algebra with Examples of Subgroups
Please Subscribe here, thank you!!! https://goo.gl/JQ8Nys Definition of a Subgroup in Abstract Algebra with Examples of Subgroups
From playlist Abstract Algebra