The measurement of a circle involves several key concepts and formulas that describe its dimensions. The primary measurements of a circle include: 1. **Radius (r)**: The distance from the center of the circle to any point on its circumference. 2. **Diameter (d)**: The distance across the circle, passing through the center. The diameter is twice the radius: \[ d = 2r \] 3.
"On Spirals" is a work by the philosopher and cultural critic J.J. (John James) Merrell, exploring the nature of spirals in various contexts, particularly in philosophy, science, art, and architecture. The book delves into how spirals symbolize growth, evolution, and the interconnectedness of different systems or ideas. The concept of spirals can also be metaphorical, representing nonlinear progress or the complexity of experiences in life and thought.
A two-point tensor, often referred to as a second-order tensor, is a mathematical object that can be represented as a rectangular array of numbers arranged in a 2-dimensional grid. In the context of physics and engineering, tensors are used to describe physical quantities that have multiple components and can occur in various coordinate systems. A two-point tensor typically has two indices, which can be thought of as pairs of values that represent how the tensor transforms under changes in coordinate systems.
K-homology is a cohomology theory in the field of algebraic topology that provides a way to study topological spaces using tools from K-theory. It is a variant of K-theory where one considers the behavior of vector bundles and their generalizations over spaces. K-homology is mainly applied in the framework of noncommutative geometry and has connections to several areas such as differential geometry, the theory of operator algebras, and index theory.
The term "exterior space" can refer to different concepts depending on the context in which it is used. Here are a few interpretations: 1. **Architecture and Urban Planning**: In this context, exterior space often refers to outdoor areas surrounding buildings or structures. This can include gardens, parks, plazas, patios, and other outdoor environments that are designed for public or private use. It emphasizes the design and arrangement of these spaces to enhance usability, aesthetic appeal, and connectivity with the built environment.
In category theory and related fields in mathematics, a **pointed space** is a type of topological space that has a distinguished point. More formally, a pointed space is a pair \((X, x_0)\), where \(X\) is a topological space and \(x_0 \in X\) is a specified point called the **base point** or **point of interest**.
A **simplicial presheaf** is a specific type of presheaf that arises in the context of simplicial sets and homotopy theory. It is a functor from the category of simplicial sets (or a related category) to another category (usually the category of sets, or perhaps some other category of interest such as topological spaces, abelian groups, etc.).
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.
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.
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.
The Kurosh subgroup theorem is a result in group theory, specifically concerning the structure of subgroups of a given group. It provides a description of the subgroups of a free group or a subgroup of a free group.
Singular integrals are a class of integrals that arise in various fields, such as mathematics, physics, and engineering. They often involve integrands that have singularities—points at which they become infinite or undefined. The study of singular integrals is particularly important in the analysis of boundary value problems, harmonic functions, and potential theory. ### Characteristics: 1. **Singularities**: The integrands typically exhibit singular behavior at certain points.
Orlicz spaces are a type of functional space that generalizes classical \( L^p \) spaces, where the integrability condition is governed by a function known as a 'Young function'. An Orlicz space is often denoted as \( L(\Phi) \), where \( \Phi \) is a given Young function.
Digital collectible card games (CCGs) are a genre of digital games that combine elements of traditional collectible card games with digital gameplay mechanics. In these games, players build their decks by acquiring cards, which can represent characters, abilities, items, or spells, and use these decks to compete against other players or challenges in the game.
"Star Wars: Force Collection" is a mobile trading card game that was released in 2014. Developed by Konami, it allows players to assemble a collection of cards featuring characters, vehicles, and creatures from the Star Wars universe. Players can engage in battles, complete missions, and participate in events using their collected cards. The gameplay involves strategic deck building, where players create decks with different characters that have unique abilities.
Puzzle designers are creators who conceptualize, design, and develop puzzles for various formats, including games, escape rooms, online platforms, and printed materials. Their work involves crafting engaging and challenging puzzles that often require logical reasoning, problem-solving skills, and creativity to solve. Puzzle designers may work in various fields, including: 1. **Board Games and Video Games**: They create puzzles that are integral to gameplay and narrative progression.
A list of game designers typically includes individuals known for their significant contributions to the video game industry. Here are some notable game designers: 1. **Shigeru Miyamoto** - Creator of iconic series such as Mario, The Legend of Zelda, and Donkey Kong. 2. **Hideo Kojima** - Known for the Metal Gear series, particularly Metal Gear Solid, and Death Stranding.
Doubling space is a concept often used in various fields, including mathematics, computer science, and physics, and it can refer to different ideas depending on the context. 1. **Mathematics and Geometry**: In the context of mathematical spaces, doubling often refers to the property of metric spaces where ball sizes can be controlled by the number of smaller balls that can cover the larger ones.
The Kirszbraun theorem, also known as Kirszbraun's extension theorem, is a result in the field of metric geometry and functional analysis. It addresses the extension of Lipschitz continuous functions.

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