In the context of mathematics, particularly in topology and algebraic geometry, the term "universal bundle" can refer to different concepts depending on the specific field of study. However, it commonly pertains to a type of fiber bundle that serves as a sort of "universal" example for a given class of objects. 1. **Universal Bundle in Algebraic Geometry**: In algebraic geometry, a universal bundle often refers to a family of algebraic varieties parameterized by a base space.
The braid group is a mathematical structure that arises in the study of braids, which can be visualized as strands intertwined in a particular way. It is a fundamental concept in the fields of topology, algebra, and mathematical physics.
Dowker–Thistlethwaite notation is a method used in knot theory to represent knots and links in a compact form. This notation encodes information about a knot's crossings and their order, facilitating the study of knot properties and transformations. In Dowker–Thistlethwaite notation, a knot is represented by a sequence of integers, which are derived from a specific way of traversing the knot diagram.
A list of prime knots refers to a classification of knots in the field of topology, specifically knot theory. In knot theory, a knot is typically defined as a loop in three-dimensional space that does not intersect itself. Knots can be composed in various ways, and when a knot cannot be decomposed into simpler knots (i.e., cannot be divided into two non-trivial knots that are linked together), it is referred to as a "prime knot.
The Milnor map arises in the study of the topology of manifolds, particularly in the context of smooth invariants and characteristic classes. Named after John Milnor, it provides a way to analyze the relationships between different types of differentiable structures on manifolds.
The Unknotting Problem is a well-known problem in the field of topology, particularly in knot theory, which is a branch of mathematics that studies the properties and classifications of knots. The problem can be stated as follows: **Problem Statement**: Given a knot (a closed loop in three-dimensional space that does not intersect itself), determine whether the knot is equivalent to an "unknotted" loop (a simple, non-intersecting circle).
"Writhe" can refer to several different concepts depending on the context: 1. **Biological Context**: In biology, "writhe" often describes the movement of animals, particularly when they are twisting or contorting their bodies in reaction to pain or distress. For example, snakes or worms might writhe on the ground.
In mechanical engineering, "duality" typically refers to concepts found in mechanics and optimization, where a problem can be expressed in two different but mathematically related ways. These dual representations can provide different insights or simplify analysis and solution processes. Here are a few contexts in which duality appears: ### 1.
In algebraic geometry and number theory, a **group scheme** is a scheme that has the structure of a group, in the sense that it supports the operations of multiplication and inversion in a way that is compatible with the geometric structure.
Lefschetz duality is a powerful result in algebraic topology that relates the homology of a manifold and its dual in a certain sense. More specifically, it applies to compact oriented manifolds and provides a relationship between their topological features.
In category theory, a **dominant functor** is a specific type of functor that reflects a certain degree of "size" or "intensity" of structure between categories.
A **profunctor** is a concept that arises in category theory, which is a branch of mathematics. It is a generalization of a functor. Specifically, a profunctor can be understood as a type of structure that relates two categories. You can think of a profunctor as a functor that is "indexed" by two categories.
In the context of category theory, a translation functor is not a standard term, and its meaning might depend on the specific field of mathematics involved. However, we can interpret it in a few related contexts: 1. **Translation in Topology or Algebra**: In a topological or algebraic setting, one might consider a functor that shifts or translates structures from one category to another.
The Zuckerman functor, often denoted as \( Z \), is a construction in the realm of representation theory, particularly in the context of Lie algebras and their representations. It is named after the mathematician Greg Zuckerman, who introduced it in relation to the study of representations of semisimple Lie algebras. The Zuckerman functor is a method for producing certain types of representations from a given representation of a Lie algebra.
An ∞-topos is a concept in higher category theory that generalizes the notion of a topos, which originates from category theory and algebraic topology. In classical terms, a topos can be considered as a category that behaves like the category of sheaves on a topological space, possessing certain properties such as limits, colimits, exponentials, and a subobject classifier.
In category theory, a **pullback** is a way of constructing a new object (or diagram) that represents the idea of "pulling back" information from two morphisms through a common codomain. It can be thought of as a limit in the category of sets (or in any category where limits exist), and it captures how two morphisms can be jointly represented.
In group theory, a **fitting subgroup** is a concept related to the structure of finite groups. Specifically, the Fitting subgroup of a group \( G \), denoted as \( F(G) \), is defined as the largest nilpotent normal subgroup of \( G \). ### Key Points about Fitting Subgroup: 1. **Nilpotent Group**: A group is nilpotent if its upper central series terminates in the whole group after finitely many steps.
Denormalization is a database design strategy used to improve the performance of a database by reducing the complexity of its schema. It involves intentionally introducing redundancy into a relational database by merging or combining tables, or by adding redundant fields to a table that already exists. The basic idea behind denormalization is to minimize the number of join operations needed to retrieve data, which can improve query performance, especially in read-heavy applications.
The Prüfer rank, also known as the Prüfer order, is a concept from the field of algebraic topology and algebraic K-theory that applies to modules, particularly in relation to Prüfer domains. It is a measure of the "size" of a module, similar to the rank of a vector space, but adapted for module theory.
Thompson groups are a family of groups that arise in the area of geometric group theory, named after the mathematician J. G. Thompson who introduced them. They are defined in the context of homeomorphisms of the unit interval \([0, 1]\) and can be understood as groups of piecewise linear homeomorphisms.

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