In mathematics, particularly in the fields of topology and differential geometry, the term "submersion" refers to a specific type of smooth map between differentiable manifolds. A smooth map \( f: M \to N \) is called a submersion at a point \( p \in M \) if its differential \( df_p: T_pM \to T_{f(p)}N \) is surjective.
Cybiko is a brand of handheld wireless communication devices that were popular in the early 2000s. It was designed for teenagers and featured various functions, including messaging, gaming, and basic internet capabilities. The devices had a small form factor, resembling a cross between a pager and a handheld gaming console. Cybiko devices operated on a proprietary wireless network, allowing users to connect with each other for messaging and multiplayer games within a limited range.
FireChat is a messaging application that allows users to communicate even without an internet connection or a mobile network. It uses mesh networking technology, which enables devices to connect directly to each other via Bluetooth and Wi-Fi. This means that users can send messages to others nearby, and the app relays messages through nearby devices, effectively creating a decentralized communication network. FireChat gained attention during events where traditional communication networks were overwhelmed or unavailable, such as protests or natural disasters.
Z-Wave is a wireless communication protocol designed for home automation and smart home devices. It operates on a low-energy, low-frequency radio signal, making it well-suited for control and monitoring applications in residential environments. Here are some key features and characteristics of Z-Wave: 1. **Mesh Networking**: Z-Wave devices form a mesh network, where each device can communicate with others within range. This allows for extended coverage and improved reliability, as signals can hop from one device to another.
Sucharit Sarkar is a name associated with the field of astrophysics and astronomy, particularly known for contributions in cosmology and theoretical physics. However, the details about his work or background may not be widely recognized in public domains.
The Trisectrix of Maclaurin is a specific mathematical curve that is notable for its property of trisecting angles. In polar coordinates, it can be expressed as a curve defined by the equation: \[ r = a \cdot \theta \] where \( r \) is the distance from the origin, \( \theta \) is the angle in polar coordinates, and \( a \) is a constant.
Hilbert's fifth problem is one of the famous problems posed by the mathematician David Hilbert in his list of 23 unsolved problems presented in 1900. The fifth problem specifically concerns the characterization of continuous transformations and their relation to group theory, particularly the concept of topological groups.
Double-negation translation is a concept primarily associated with the field of logic and philosophy, particularly in relation to the principles of translation between different logical systems or languages. It often comes into play when discussing how to interpret and translate statements, particularly those involving negation, across systems that might have different rules or structures. In simple terms, double-negation translation refers to the process of translating a negation (not P) in a way that uses two negations to clarify or preserve meaning.
Michael Dummett (1925–2011) was a prominent British philosopher known for his work in philosophy of language, philosophy of mathematics, and metaphysics, as well as for his contributions to the study of logic and epistemology. He was particularly influential in the development of anti-realism in the philosophy of language, which argues that the meaning of statements is tied to their language and use rather than to an independent reality.
Stephen Cole Kleene (1909–1994) was an American mathematician and logician who made significant contributions to the fields of mathematical logic, recursion theory, and theoretical computer science. He is renowned for his work in the areas of automata theory and formal languages. Kleene is particularly well-known for developing the concept of regular sets and regular expressions, which are essential in the theory of computation.
Lancelot Hogben (1895–1975) was a British biologist, statistician, and author known for his contributions to science and education in the mid-20th century. He was particularly influential in promoting the use of statistics in biology and the social sciences. Hogben advocated for the importance of scientific literacy and popularized complex scientific concepts through accessible writing.
The concept of "necessity of identity" can be understood in different contexts, particularly in philosophy, psychology, sociology, and other fields. Here are a few interpretations: 1. **Philosophical Context**: In philosophy, particularly in metaphysics, identity refers to the concept of what it means for something to be the same as itself. The necessity of identity involves discussions about the nature of objects, individuals, and their properties.
A standing wave is a wave that remains in a constant position and does not propagate through space. Unlike traveling waves, which move through a medium and transfer energy from one point to another, standing waves appear to "stand still." They are formed by the interference of two waves traveling in opposite directions, typically when waves reflect off a boundary.
Personal identity refers to the concept and understanding of what makes one individual distinct from others over time. It encompasses the various attributes, experiences, beliefs, and characteristics that contribute to an individual's sense of self. The study of personal identity often intersects with philosophical, psychological, and sociological perspectives. Key aspects of personal identity include: 1. **Continuity**: This involves the notion of persistence through time.
Logic and sexual morality intersect in various ways, particularly in discussions about ethical frameworks, arguments, and principles concerning sexual behavior. Here’s a breakdown of both concepts: ### Logic 1. **Definition**: Logic is the study of reasoning and arguments. It involves the principles of valid reasoning, including formal systems (like propositional and predicate logic) and informal reasoning (like inductive and deductive logic).
"Logical Investigations" is a seminal work by the German philosopher Edmund Husserl, first published in 1900 and later expanded in 1913. It is considered one of the foundational texts of phenomenology, which Husserl developed as a philosophical method aimed at studying consciousness and the structures of experience. The work is divided into two parts.
The term "Sum of Logic" could refer to a few different concepts depending on the context, as it's not a widely recognized term in philosophy or mathematics by itself. Here are a few interpretations: 1. **Logical Operations**: In logic, particularly Boolean algebra, "sum" can refer to the logical OR operation. The "sum" of logical values (true or false) can be understood in terms of combining conditions where at least one condition being true results in a true outcome.
"The Logical Structure of Linguistic Theory" (LSLT) is a seminal work by the linguist Noam Chomsky, written during the late 1950s and published in 1975. The work is significant in the field of linguistics and has had a profound impact on the study of language. In LSLT, Chomsky explores the formal properties of natural languages and their underlying structures.
Algebra and tiling are two distinct concepts that can be explored within the realm of mathematics, but they can also intersect in interesting ways. ### Algebra: Algebra is a branch of mathematics dealing with symbols and the rules for manipulating those symbols. It involves the study of mathematical symbols and the rules for manipulating these symbols to solve equations and understand relationships between quantities. The key components of algebra include: 1. **Variables**: Symbols (often letters) that represent unknown values.
Vectorial mechanics, often referred to as vector mechanics, is a branch of mechanics that deals with the analysis of forces and motion using vector quantities. It focuses on representing physical quantities such as displacement, velocity, acceleration, and force as vectors, which are defined by their magnitude and direction. This approach is particularly useful in solving problems involving multiple forces acting on a body, as it allows for the decomposition of vectors into components and the application of vector algebra.

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