In category theory, a **representable functor** is a functor that is naturally isomorphic to the Hom functor between two categories. To understand this concept more fully, let's first break down some key elements. ### Basic Concepts 1. **Categories**: In category theory, a category consists of objects and morphisms (arrows) between those objects, satisfying certain properties.
A dinatural transformation is a concept in category theory, specifically in the context of functors and natural transformations. It generalizes the notion of a natural transformation to situations involving two different functors that are indexed by a third category. In more detail, consider two categories \( \mathcal{C} \) and \( \mathcal{D} \), along with a third category \( \mathcal{E} \).
Extranatural transformation refers to a concept in the field of mathematics, particularly in category theory and algebraic topology. While it is not as commonly discussed as some other concepts, the idea generally pertains to the transformation of objects or morphisms within a specific framework that extends beyond traditional natural transformations. In category theory, a **natural transformation** is a way of transforming one functor into another while preserving the structure of the categories involved.
A **strict 2-category** is a generalization of a category that allows for a richer structure by incorporating not just objects and morphisms (arrows) between them, but also higher-dimensional morphisms called 2-morphisms (or transformations) between morphisms. In a strict 2-category, all the structural relationships between objects, morphisms, and 2-morphisms are explicitly defined and obey strict associativity and identity laws.
Weak \( n \)-categories are a generalization of the concept of \( n \)-categories in the field of higher category theory. In traditional category theory, a category consists of objects and morphisms between those objects, satisfying certain axioms. As we move to higher dimensions, such as \( 2 \)-categories or \( 3 \)-categories, we introduce higher-dimensional morphisms (or "cells"), leading to more complex structures.
In algebraic geometry and commutative algebra, a **local ring** is a particular type of ring that has a unique maximal ideal. More formally, if \( R \) is a commutative ring with identity, it is called a local ring if it contains a single maximal ideal \( \mathfrak{m} \). This property leads to a structure that facilitates the study of functions and algebraic entities that are "localized" around a certain point.
Higman's embedding theorem is a result in the field of formal languages and automata theory, specifically relating to the study of recursively enumerable languages and context-free languages. The theorem provides a way to understand the structure of certain algebraic objects associated with these languages.
Fourth Normal Form (4NF) is a type of database normalization used to minimize redundancy and dependency by organizing data in a relational database. A database table is said to be in Fourth Normal Form if it meets the following criteria: 1. **It is in Boyce-Codd Normal Form (BCNF)**: Before a table can be in 4NF, it must first satisfy all the conditions of BCNF.
As of my last knowledge update in October 2023, "Ultralimit" could refer to various concepts depending on the context in which it is used. However, there wasn't a widely recognized or specific definition for "Ultralimit" in major fields such as technology, science, or popular culture.
Dana Scott is a prominent figure in the fields of mathematics and computer science, particularly known for his work in domain theory, which is a branch of order theory that has important applications in the semantics of programming languages. His contributions also include work on the concept of non-standard analysis and the development of various mathematical frameworks. In addition to his academic achievements, Dana Scott was awarded the prestigious Knuth Prize in 2006 for his influential work in the area of theoretical computer science.
Thoralf Skolem (1887–1963) was a Norwegian mathematician known for his significant contributions to mathematical logic, set theory, and model theory. He is best remembered for developing Skolem's paradox and for his work on the foundations of mathematics. One of his notable contributions is in the area of first-order logic and model theory, particularly regarding the completeness of first-order logic and the Löwenheim-Skolem theorem.
Third Normal Form (3NF) is a database normalization standard used to reduce data redundancy and improve data integrity. A database is in Third Normal Form if it satisfies the following conditions: 1. **It is in Second Normal Form (2NF)**: This means that the database is already in First Normal Form (1NF), and all non-key attributes are fully functionally dependent on the primary key.
Pseudo-differential operators (PDOs) are a class of operators that generalize differential operators. They play a crucial role in the analysis of partial differential equations (PDEs), especially in the study of solutions and their regularity properties. PDOs are particularly useful in the context of Fourier analysis and microlocal analysis. ### Definition A pseudo-differential operator is typically defined in terms of its action on test functions through a symbolic calculus.
A singular integral refers to an integral where the integrand has a singularity (point of discontinuity or unbounded behavior) within the domain of integration. The term is often discussed in the context of mathematical analysis and can appear in various forms, including in the theory of functions of a real variable, complex analysis, and the study of partial differential equations.
Outermorphism is a concept in the field of mathematics, specifically in category theory, which deals with the structure and relationships between different mathematical objects. While "outermorphism" is not a standard term widely recognized in mathematics, it may refer to a specific type of morphism that relates to certain structures or transformations in a broader context. In general, the term "morphism" in category theory refers to a structural-preserving map between two objects.
In abstract algebra, particularly in the context of ring theory, a **prime ideal** is a special type of ideal that has important properties related to the structure of rings.
Gin Rummy is a popular card game that has been adapted into various video game formats. The game typically involves two players who try to form sets of cards (three or four cards of the same rank) and runs (three or more cards in sequential order of the same suit). The objective is to reach a certain number of points by being the first to "knock" (end the round) or by forming valid sets and runs with the cards in hand.
Kardboard Kings is a video game that combines elements of simulation and management, where players take on the role of a trading card shop owner. In the game, players manage their store by buying, selling, and trading cards while also interacting with customers and other vendors. The game features a variety of mechanics, including building inventory, customizing the shop, and participating in events like tournaments.
Marion Tinsley was a renowned American checkers (also known as draughts) player, widely regarded as one of the greatest players in the history of the game. Born on April 3, 1929, and passing away on March 2, 1995, Tinsley was particularly known for his mastery of the 8x8 checkers variant. He won numerous national and international titles and was a multiple-time world champion.
AlphaGo is an artificial intelligence program developed by DeepMind Technologies, a subsidiary of Alphabet Inc. (Google's parent company). It is designed to play the complex board game Go, which is known for its deep strategic elements and historically has been considered a major challenge for AI due to its vast number of possible moves and board configurations. AlphaGo made headlines for its ability to defeat some of the world's top Go players, including the reigning world champion Lee Sedol in 2016.

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