Hall algebra is a mathematical structure that arises in the context of category theory and representation theory, particularly in the study of representations of finite groups and combinatorial structures. It is named after Philip Hall, who introduced the concept of Hall systems in the 1930s. At its core, Hall algebra is built on the idea of Hall pairs, which are certain collections of subsets of a finite set that satisfy specific combinatorial properties.
Plethysm is a term that can refer to a couple of different concepts, depending on the context: 1. **In Medical or Biological Context**: Plethysm is often associated with a measurement of volume changes in organs or limbs, particularly in relation to blood flow, swelling, or capacity. The technique used to measure these changes is called plethysmography, which can assess conditions such as peripheral artery disease or venous insufficiency.
The symmetric product of an algebraic curve is a mathematical construction that generalizes the notion of products of points on the curve. More specifically, if \( C \) is a projective algebraic curve, the symmetric product \( \text{Sym}^n(C) \) of \( C \) is the space that parameterizes unordered \( n \)-tuples of points on the curve, where the points can be repeated.
The LaTeX Project Public License (LPPL) is a software license specifically created for the LaTeX typesetting system and its associated packages. It was designed to ensure that LaTeX remains free to use and distribute, while also maintaining certain standards for authors who contribute to the LaTeX ecosystem.
The PracTeX Journal is a scholarly publication focused on practical aspects of using TeX, LaTeX, and related typesetting systems. It aims to share articles, tutorials, and insights that help users enhance their typesetting skills and explore new techniques in document preparation. The journal serves as a platform for practitioners, developers, and educators in the TeX community to exchange ideas and experiences.
Lewis Paul was an English inventor and one of the key figures in the development of the mechanized textile industry during the 18th century. He is best known for his invention of the "carding machine" and improvements to the spinning process, which were significant factors in the Industrial Revolution. His inventions helped streamline the production of textiles, making it easier to process raw wool and cotton into yarn.
Textile manufacturing is the process of converting raw fibers into usable fabrics or textiles. This industry encompasses a wide range of processes and techniques, including the following key stages: 1. **Fiber Production**: This can involve natural fibers (like cotton, wool, linen, and silk) or synthetic fibers (such as polyester, nylon, and acrylic). Natural fibers are harvested from plants or animals, while synthetic fibers are manufactured through chemical processes.
The Australian Ballet School (ABS) is the official school of the Australian Ballet and is known for training aspiring ballet dancers in Australia. Alumni of the Australian Ballet School are individuals who have completed their training at ABS and often go on to have successful careers in ballet and dance, both within Australia and internationally. Many alumni have joined prestigious ballet companies, including the Australian Ballet, as well as renowned international companies. They may also pursue careers in choreography, teaching, or dance education.
The Australian Ballet School is the official school of The Australian Ballet, one of the country's premier ballet companies. Founded in 1964, the school is located in Melbourne and provides specialized training for aspiring ballet dancers. It offers a range of programs, including full-time training for students aged 15 and older who are serious about pursuing a professional career in ballet. The curriculum includes classical ballet technique, contemporary dance, physical conditioning, and repertoire, along with opportunities for students to perform.
BaZnGa is a chemical compound composed of barium (Ba), zinc (Zn), and gallium (Ga). The specific structure and properties of BaZnGa would depend on the particular stoichiometry and crystalline form. Generally, compounds that consist of multiple metals can exhibit interesting physical, chemical, and electronic properties, potentially making them useful in various applications such as electronics, catalysis, or materials science.
The Classification of Finite Simple Groups is a monumental result in the field of group theory, specifically in the area of finite groups. It establishes a comprehensive framework for understanding the structure of finite simple groups, which are the building blocks of all finite groups in a manner akin to how prime numbers function in number theory.
The Harish-Chandra isomorphism is a fundamental result in the representation theory of Lie groups and Lie algebras, particularly in the context of semisimple Lie groups. It relates the spaces of invariant differential operators on a symmetric space to the space of functions on the Lie algebra of the group. More specifically, consider a semisimple Lie group \( G \) and a maximal compact subgroup \( K \).
Markov's inequality is a result in probability theory that provides an upper bound on the probability that a non-negative random variable is greater than or equal to a positive constant. The inequality is named after the Russian mathematician Andrey Markov. The statement of Markov's inequality is as follows: Let \(X\) be a non-negative random variable (i.e., \(X \geq 0\)), and let \(a > 0\) be a positive constant.
The Narasimhan-Seshadri theorem is a fundamental result in the theory of vector bundles over complex curves (or Riemann surfaces). It establishes a deep connection between the geometry of vector bundles and the representation theory of groups, particularly in the context of holomorphic vector bundles on Riemann surfaces and unitary representations of the fundamental group.
The Denjoy-Wolff theorem is a result in complex analysis, particularly in the field of iterated function systems and the study of holomorphic functions. It characterizes the dynamics of holomorphic self-maps of the unit disk, specifically focusing on the behavior of iterates of such functions.
The Double Limit Theorem, often referred to in the context of limits in calculus, relates to the properties and behavior of limits involving functions of two variables.
The Unique Homomorphic Extension Theorem is a result in the field of algebra, particularly concerning rings and homomorphisms. It typically states that if you have a ring \( R \) and a subring \( S \), along with a homomorphism defined on \( S \), then there exists a unique (in the case of certain conditions) homomorphic extension of this mapping up to the whole ring \( R \).

Pinned article: Introduction to the OurBigBook Project

Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
We have two killer features:
  1. topics: topics group articles by different users with the same title, e.g. here is the topic for the "Fundamental Theorem of Calculus" ourbigbook.com/go/topic/fundamental-theorem-of-calculus
    Articles of different users are sorted by upvote within each article page. This feature is a bit like:
    • a Wikipedia where each user can have their own version of each article
    • a Q&A website like Stack Overflow, where multiple people can give their views on a given topic, and the best ones are sorted by upvote. Except you don't need to wait for someone to ask first, and any topic goes, no matter how narrow or broad
    This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.
    Figure 1.
    Screenshot of the "Derivative" topic page
    . View it live at: ourbigbook.com/go/topic/derivative
  2. local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:
    This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
    Figure 2.
    You can publish local OurBigBook lightweight markup files to either https://OurBigBook.com or as a static website
    .
    Figure 3.
    Visual Studio Code extension installation
    .
    Figure 4.
    Visual Studio Code extension tree navigation
    .
    Figure 5.
    Web editor
    . You can also edit articles on the Web editor without installing anything locally.
    Video 3.
    Edit locally and publish demo
    . Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension.
    Video 4.
    OurBigBook Visual Studio Code extension editing and navigation demo
    . Source.
  3. https://raw.githubusercontent.com/ourbigbook/ourbigbook-media/master/feature/x/hilbert-space-arrow.png
  4. Infinitely deep tables of contents:
    Figure 6.
    Dynamic article tree with infinitely deep table of contents
    .
    Descendant pages can also show up as toplevel e.g.: ourbigbook.com/cirosantilli/chordate-subclade
All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
Feel free to reach our to us for any help or suggestions: docs.ourbigbook.com/#contact