Low-dimensional topology | Geometric group theory

In geometric group theory, a discipline of mathematics, subgroup distortion measures the extent to which an overgroup can reduce the complexity of a group's word problem. Like much of geometric group theory, the concept is due to Misha Gromov, who introduced it in 1993. Formally, let S generate group H, and let G be an overgroup for H generated by S ∪ T. Then each generating set defines a word metric on the corresponding group; the distortion of H in G is the asymptotic equivalence class of the function where BX(x, r) is the ball of radius r about center x in X and diam(S) is the diameter of S. Subgroups with constant distortion are called quasiconvex. (Wikipedia).

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 | 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

Abstract Algebra | The notion of a subgroup.

We present the definition of a subgroup and give some examples. http://www.michael-penn.net http://www.randolphcollege.edu/mathematics/

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

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

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

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

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

Hyperbolic groups, Cannon-Thurston maps, and hydra - Timothy Riley

Timothy Riley Cornell University; Member, School of Mathematics November 17, 2014 Groups are Gromov-hyperbolic when all geodesic triangles in their Cayley graphs are close to being tripods. Despite being tree-like in this manner, they can harbour extreme wildness in their subgroups. I wil

From playlist Mathematics

Laurent Bartholdi - Imbeddings in groups of subexponential growth

Laurent Bartholdi (University of Gottingen, Germany) A finitely generated group has subexponential growth if the number of group elements expressible as words of length $\le n$ grows subexponentially in $n$. I will show that every countable group that does not contain a subgroup of expone

From playlist T1-2014 : Random walks and asymptopic geometry of groups.

Algebraic Ending Laminations and Quasiconvexity by Mahan Mj

Surface Group Representations and Geometric Structures DATE: 27 November 2017 to 30 November 2017 VENUE:Ramanujan Lecture Hall, ICTS Bangalore The focus of this discussion meeting will be geometric aspects of the representation spaces of surface groups into semi-simple Lie groups. Classi

From playlist Surface Group Representations and Geometric Structures

Thin Matrix Groups - a brief survey of some aspects - Peter Sarnak

Speaker: Peter Sarnak (Princeton/IAS) Title: Thin Matrix Groups - a brief survey of some aspects More videos on http://video.ias.edu

From playlist Mathematics

Counting and dynamics in SL2 - Michael Magee

Michael Magee Member, School of Mathematics April 6, 2015 In this talk I'll discuss a lattice point count for a thin semigroup inside SL2(ℤ)SL2(Z). It is important for applications I'll describe that one can perform this count uniformly throughout congruence classes. The approach to count

From playlist Mathematics

Gianluca Paolini: Torsion-free Abelian groups are Borel complete

HYBRID EVENT Recorded during the meeting "XVI International Luminy Workshop in Set Theory" the September 14, 2021 by the Centre International de Rencontres Mathématiques (Marseille, France) Filmmaker: Guillaume Hennenfent Find this video and other talks given by worldwide mathematicia

From playlist Logic and Foundations

J. Wu: The Novikov conjecture and C*-algebras of infinite dimensional nonpositively curved spaces

Talk by Jianchao Wu in Global Noncommutative Geometry Seminar (Americas) http://www.math.wustl.edu/~xtang/NCG-Seminar.html on June 10, 2020.

From playlist Global Noncommutative Geometry Seminar (Americas)

Plenary lecture 1 by Martin Bridson - Part 2

Geometry Topology and Dynamics in Negative Curvature URL: https://www.icts.res.in/program/gtdnc DATES: Monday 02 Aug, 2010 - Saturday 07 Aug, 2010 VENUE : Raman Research Institute, Bangalore DESCRIPTION: This is An ICM Satellite Conference. The conference intends to bring together ma

From playlist Geometry Topology and Dynamics in Negative Curvature

Definition of a Subgroup and Proof that the Kernel is a Subgroup

We define what it means for H to be a subgroup of G and give clear criteria which you can follow in order to prove that a given subset is a subgroup. Then we prove that the kernel of f is a subgroup of G. I hope this helps someone learning abstract algebra. Useful Math Supplies https://am

From playlist Group Theory Problems

“Counting and Growth Pt3” - Moon Duchin

From playlist Mathematics

Group actions on 1-manifolds: A list of very concrete open questions – Andrés Navas – ICM2018

Dynamical Systems and Ordinary Differential Equations Invited Lecture 9.8 Group actions on 1-manifolds: A list of very concrete open questions Andrés Navas Abstract: Over the last four decades, group actions on manifolds have deserved much attention by people coming from different fields

From playlist Dynamical Systems and ODE

All About Subgroups | Abstract Algebra

We introduce subgroups, the definition of subgroup, examples and non-examples of subgroups, and we prove that subgroups are groups. We also do an example proving a subset is a subgroup. If G is a group and H is a nonempty subset of G, we say H is a subgroup of G if H is closed with respect

From playlist Abstract Algebra