Theorems in algebra | Articles containing proofs | Group theory
The crystallographic restriction theorem in its basic form was based on the observation that the rotational symmetries of a crystal are usually limited to 2-fold, 3-fold, 4-fold, and 6-fold. However, quasicrystals can occur with other diffraction pattern symmetries, such as 5-fold; these were not discovered until 1982 by Dan Shechtman. Crystals are modeled as discrete lattices, generated by a list of independent finite translations. Because discreteness requires that the spacings between lattice points have a lower bound, the group of rotational symmetries of the lattice at any point must be a finite group (alternatively, the point is the only system allowing for infinite rotational symmetry). The strength of the theorem is that not all finite groups are compatible with a discrete lattice; in any dimension, we will have only a finite number of compatible groups. (Wikipedia).
Pierre Berthelot - Non characteristic finiteness theorems in crystalline cohomology
On the crystalline site relative to Z/p^n, I will explain the construction of two triangulated subcategories of the derived category of complexes of filtered modules on the structural sheaf, linked by a local biduality theorem. For these complexes, one can prove finiteness theorems for inv
From playlist A conference in honor of Arthur Ogus on the occasion of his 70th birthday
Determining Limits of Trigonometric Functions
An introductory video on determining limits of trigonometric functions. http://mathispower4u.wordpress.com/
From playlist Limits
Computing Limits from a Graph with Infinities
In this video I do an example of computing limits from a graph with infinities.
From playlist Limits
Introduction to cluster algebras and their types (Lecture 2) by Jacob Matherne
PROGRAM :SCHOOL ON CLUSTER ALGEBRAS ORGANIZERS :Ashish Gupta and Ashish K Srivastava DATE :08 December 2018 to 22 December 2018 VENUE :Madhava Lecture Hall, ICTS Bangalore In 2000, S. Fomin and A. Zelevinsky introduced Cluster Algebras as abstractions of a combinatoro-algebra
From playlist School on Cluster Algebras 2018
Evaluate the limit with tangent
👉 Learn how to evaluate the limit of a function involving trigonometric expressions. The limit of a function as the input variable of the function tends to a number/value is the number/value which the function approaches at that time. The limit of a function is usually evaluated by direct
From playlist Evaluate Limits with Trig
An Elementary Proof of the Restricted Invertibility Theorem - Nikhil Srivastava
Nikhil Srivastava Institute for Advanced Study November 9, 2010 We give an elementary proof of a generalization of Bourgain and Tzafriri's Restricted Invertibility Theorem, which says roughly that any matrix with columns of unit length and bounded operator norm has a large coordinate subs
From playlist Mathematics
Lars Thorge Jensen: Cellularity of the p-Kazhdan-Lusztig Basis for Symmetric Groups
After recalling the most important results about Kazhdan-Lusztig cells for symmetric groups, I will introduce the p-Kazhdan-Lusztig basis and give a complete description of p-cells for symmetric groups. After that I will mention important consequences of the Perron-Frobenius theorem for p-
From playlist Workshop: Monoidal and 2-categories in representation theory and categorification
Use limit laws and special trig limits to evaluate
👉 Learn how to evaluate the limit of a function involving trigonometric expressions. The limit of a function as the input variable of the function tends to a number/value is the number/value which the function approaches at that time. The limit of a function is usually evaluated by direct
From playlist Evaluate Limits with Trig
Matrix stability of crystallographic groups - Soren Eilers
Stability and Testability Topic: Matrix stability of crystallographic groups Speaker: Soren Eilers Affiliation: University of Copenhagen Date: February 17, 2021 For more video please visit http://video.ias.edu
From playlist Stability and Testability
Graham ELLIS - Computational group theory, cohomology of groups and topological methods 1
The lecture series will give an introduction to the computer algebra system GAP, focussing on calculations involving cohomology. We will describe the mathematics underlying the algorithms, and how to use them within GAP. Alexander Hulpke's lectures will being with some general computation
From playlist École d'Été 2022 - Cohomology Geometry and Explicit Number Theory
Geometry and arithmetic of sphere packings - Alex Kontorovich
Members' Seminar Topic: Geometry and arithmetic of sphere packings Speaker: A nearly optimal lower bound on the approximate degree of AC00 Speaker:Alex Kontorovich Affiliation: Rutgers University Date: October 23, 2017 For more videos, please visit http://video.ias.edu
From playlist Mathematics
Bettina EICK - Computational group theory, cohomology of groups and topological methods 5
The lecture series will give an introduction to the computer algebra system GAP, focussing on calculations involving cohomology. We will describe the mathematics underlying the algorithms, and how to use them within GAP. Alexander Hulpke's lectures will being with some general computation
From playlist École d'Été 2022 - Cohomology Geometry and Explicit Number Theory
Evaluating the limit using special trig limits
👉 Learn how to evaluate the limit of a function involving trigonometric expressions. The limit of a function as the input variable of the function tends to a number/value is the number/value which the function approaches at that time. The limit of a function is usually evaluated by direct
From playlist Evaluate Limits with Trig
Diophantine analysis in thin orbits - Alex Kontorovich
Special Seminar Topic: Diophantine analysis in thin orbits Speaker: Alex Kontorovich Affiliation: Rutgers University; von Neumann Fellow, School of Mathematics Date: December 8, 2017 For more videos, please visit http://video.ias.edu
From playlist Mathematics
Limit doesn't exist 2 variables example
Example of how to show a limit doesn't exist for a function of 2 variables.
From playlist Engineering Mathematics
Induction of p-Cells and Localization - Lars Thorge Jensen
Virtual Workshop on Recent Developments in Geometric Representation Theory Topic: Induction of p-Cells and Localization Speaker: Lars Thorge Jensen Affiliation: Member, School of Mathematics Date: November 19, 2020 For more video please visit http://video.ias.edu
From playlist Virtual Workshop on Recent Developments in Geometric Representation Theory
Ian Agol, Lecture 2: Finiteness of Arithmetic Hyperbolic Reflection Groups
24th Workshop in Geometric Topology, Calvin College, June 29, 2007
From playlist Ian Agol: 24th Workshop in Geometric Topology
Ex: Limit of a Function of Two Variables (Origin - DNE)
This video explains how to find a limit of a function of two variables. Site: http://mathispower4u.com
From playlist Limits of Functions of Two Variables
Evaluate special trigonometric limits using algebra
👉 Learn how to evaluate the limit of a function involving trigonometric expressions. The limit of a function as the input variable of the function tends to a number/value is the number/value which the function approaches at that time. The limit of a function is usually evaluated by direct
From playlist Evaluate Limits with Trig
Yuri Berest : Spaces of quasi-invariants
CONFERENCE Recording during the thematic meeting : « Chromatic Homotopy, K-Theory and Functors» the January 26, 2023 at the Centre International de Rencontres Mathématiques (Marseille, France) Filmmaker: Jean Petit Find this video and other talks given by worldwide mathematicians on CIR
From playlist Topology