In the branch of mathematics known as order theory, a semimodular lattice, is a lattice that satisfies the following condition: Semimodular lawa ∧ b <: a implies b <: a ∨ b. The notation a <: b means that b covers a, i.e. a < b and there is no element c such that a < c < b. An atomistic (hence algebraic) semimodular bounded lattice is called a matroid lattice because such lattices are equivalent to (simple) matroids. An atomistic semimodular bounded lattice of finite length is called a geometric lattice and corresponds to a matroid of finite rank. Semimodular lattices are also known as upper semimodular lattices; the dual notion is that of a lower semimodular lattice. A finite lattice is modular if and only if it is both upper and lower semimodular. A finite lattice, or more generally a lattice satisfying the ascending chain condition or the descending chain condition, is semimodular if and only if it is M-symmetric. Some authors refer to M-symmetric lattices as semimodular lattices. (Wikipedia).
Mod-01 Lec-5ex Diffraction Methods For Crystal Structures - Worked Examples
Condensed Matter Physics by Prof. G. Rangarajan, Department of Physics, IIT Madras. For more details on NPTEL visit http://nptel.iitm.ac.in
From playlist NPTEL: Condensed Matter Physics - CosmoLearning.com Physics Course
Lattice Structures in Ionic Solids
We've learned a lot about covalent compounds, but we haven't talked quite as much about ionic compounds in their solid state. These will adopt a highly ordered and repeating lattice structure, but the geometry of the lattice depends entirely on the types of ions and their ratio in the chem
From playlist General Chemistry
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
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
All crystalline materials have 3D, long range, periodic order. Therefore, they have a lattice which is a grid of repeating atomic positions. We can pick a small repeating area in this grid and it becomes a unit cell. The primitive unit cell should be the smallest repeatable unit cell.
From playlist Materials Sciences 101 - Introduction to Materials Science & Engineering 2020
Gregory Henselman-Petrusek (9/28/22): Saecular persistence
Homology with field coefficients has become a mainstay of modern TDA, thanks in part to structure theorems which decompose the corresponding persistence modules. This naturally begs the question -- what of integer coefficients? Or homotopy? We introduce saecular persistence, a categoric
From playlist AATRN 2022
Inner Semidirect Product Example: Dihedral Group
Semidirect products explanation: https://youtu.be/Pat5Qsmrdaw Semidirect products are very useful in group theory. To understand why, it's helpful to see an example. Here we show how to write the dihedral group D_2n as a semidirect product, and how we can describe that purely using cyclic
From playlist Group Theory
What Are Allotropes of Metalloids and Metals | Properties of Matter | Chemistry | FuseSchool
What Are Allotropes of Metalloids and Metals Learn the basics about allotropes of metalloids and metals, as a part of the overall properties of matter topic. An allotrope is basically a different form of the same element, each with distinct physical and chemical properties. For example
From playlist CHEMISTRY
John R. Parker: Complex hyperbolic lattices
Lattices in SU(2,1) can be viewed in several different ways: via their geometry as holomorphic complex hyperbolic isometries, as monodromy groups of hypergeometric functions, via algebraic geometry as ball quotients and (sometimes) using arithmeticity. In this talk I will describe these di
From playlist Geometry
Ionic Solids, Molecular Solids, Metallic Solids, Network Covalent Solids, & Atomic Solids
This chemistry video tutorial provides a basic introduction into solids. It explains how to classify a solid as ionic solids, molecular solids or atomic solids. There are 3 different types of atomic solids that you need to be familiary with - metallic solids, Group 8A solids, and network
From playlist New AP & General Chemistry Video Playlist
Introduction to Solid State Physics, Lecture 8: Reciprocal Lattice
Upper-level undergraduate course taught at the University of Pittsburgh in the Fall 2015 semester by Sergey Frolov. The course is based on Steven Simon's "Oxford Solid State Basics" textbook. Lectures recorded using Panopto, to see them in Panopto viewer follow this link: https://pitt.host
From playlist Introduction to Solid State Physics
Introduction to Solid State Physics, Lecture 7: Crystal Structure
Upper-level undergraduate course taught at the University of Pittsburgh in the Fall 2015 semester by Sergey Frolov. The course is based on Steven Simon's "Oxford Solid State Basics" textbook. Lectures recorded using Panopto, to see them in Panopto viewer follow this link: https://pitt.host
From playlist Introduction to Solid State Physics
Phong NGUYEN - Recent progress on lattices's computations 1
This is an introduction to the mysterious world of lattice algorithms, which have found many applications in computer science, notably in cryptography. We will explain how lattices are represented by computers. We will present the main hard computational problems on lattices: SVP, CVP and
From playlist École d'Été 2022 - Cohomology Geometry and Explicit Number Theory
Gabriele NEBE - Lattices, Perfects lattices, Voronoi reduction theory, modular forms, ...
Lattices, Perfects lattices, Voronoi reduction theory, modular forms, computations of isometries and automorphisms The talks of Coulangeon will introduce the notion of perfect, eutactic and extreme lattices and the Voronoi's algorithm to enumerate perfect lattices (both Eulcidean and He
From playlist École d'Été 2022 - Cohomology Geometry and Explicit Number Theory
History of science 7: Did Witt discover the Leech lattice?
In about 1970 the German mathematician Witt claimed to have discovered the Leech lattice many years before Leech. This video explains what the Leech lattice is and examines the evidence for Witt's claim. Lieven Lebruyn discussed this question on his blog: http://www.neverendingbooks.org/w
From playlist History of science
A simple proof of a reverse Minkowski inequality - Noah Stephens-Davidowitz
Computer Science/Discrete Mathematics Seminar II Topic: A simple proof of a reverse Minkowski inequality Speaker: Noah Stephens-Davidowitz Affiliation: Visitor, School of Mathematics Date: April 17, 2018 For more videos, please visit http://video.ias.edu
From playlist Mathematics
Elliptic Curves - Lecture 14b - Elliptic curves over the complex numbers
This video is part of a graduate course on elliptic curves that I taught at UConn in Spring 2021. The course is an introduction to the theory of elliptic curves. More information about the course can be found at the course website: https://alozano.clas.uconn.edu/math5020-elliptic-curves/
From playlist An Introduction to the Arithmetic of Elliptic Curves
Counting points on the E8 lattice with modular forms (theta functions) | #SoME2
In this video, I show a use of modular forms to answer a question about the E8 lattice. This video is meant to serve as an introduction to theta functions of lattices and to modular forms for those with some knowledge of vector spaces and series. -------------- References: (Paper on MIT
From playlist Summer of Math Exposition 2 videos
Nihar Gargava - Random lattices as sphere packings
In 1945, Siegel showed that the expected value of the lattice-sums of a function over all the lattices of unit covolume in an n-dimensional real vector space is equal to the integral of the function. In 2012, Venkatesh restricted the lattice- sum function to a collection of lattices that h
From playlist Combinatorics and Arithmetic for Physics: Special Days 2022
Lattice relations + Hermite normal form|Abstract Algebra Math Foundations 224 | NJ Wildberger
We introduce lattices and integral linear spans of vexels. These are remarkably flexible, common and useful algebraic objects, and they are the direct integral analogs of vector spaces. To understand the structure of a given lattice, the algorithm to compute a Hermite normal form basis is
From playlist Math Foundations