The Müller–Schupp theorem is a result in group theory, specifically in the study of finitely generated groups. It deals with the relationship between group properties and their action on trees, particularly focusing on finitely generated groups that are defined by finite presentations. The theorem states that if a finitely generated group \( G \) acts freely and transitively on an infinite tree \( T \) (where a tree is a connected graph with no cycles), then \( G \) is a free group.
The Longest Increasing Subsequence (LIS) is a well-known problem in computer science and mathematics that involves finding the longest subsequence of a given sequence of numbers where the elements of the subsequence are in strictly increasing order. A subsequence is a sequence derived from another sequence by deleting some elements without changing the order of the remaining elements.
The term "Direct function" can refer to several contexts depending on the field or area you're discussing. Here are a few potential interpretations: 1. **Mathematics**: In algebra and calculus, a "direct function" might refer to a direct relationship between two variables where an increase in one variable results in a proportional increase in another.
Regular grammar is a type of formal grammar that is used to define regular languages, which are among the simplest classes of languages in the Chomsky hierarchy. Regular grammars consist of a set of production rules that can be used to generate strings of a language.
Rewriting is a conceptual and practical process that involves changing the form or structure of a piece of text while retaining its original meaning. It can take various forms and is commonly used in different contexts, such as: 1. **Academic Writing**: Students often rewrite their essays to improve clarity, coherence, and style, or to correct errors. 2. **Editing and Proofreading**: In publishing, editors rewrite sections of a manuscript to enhance readability, flow, or to meet specific guidelines.
Semantics encoding refers to the process of transforming information into a specific representation that reflects its meaning. This process is often used in various fields, including computer science, linguistics, psychology, and artificial intelligence, to convert data or text into a form that enables understanding and interpretation based on its inherent meaning.
Signed-digit representation is a method used to encode numbers in a way that retains both their magnitude and sign, allowing for efficient arithmetic operations, particularly in digital electronics and computer systems. In this representation, each digit can take on multiple values, typically including both positive and negative values, as well as zero. ### Key Features: 1. **Digit Values**: In signed-digit systems, digits can be represented as: - Positive digits (e.g.
A substring is a contiguous sequence of characters within a string. In programming and computer science, a string is typically a data type used to represent text, and a substring is simply any portion of that string. For example, if you have the string `"Hello, world!"`, some possible substrings include: - `"Hello"` - `"Hello, "` - `"world"` - `"lo, wo"` - `"!
WFF 'N PROOF is a logic-based game created by the American mathematician and philosopher Raymond Smullyan. The game's title stands for "Well-Formed Formulae and Proof." It is designed to teach and explore concepts in formal logic and the structure of mathematical proofs. In WFF 'N PROOF, players deal with well-formed formulas (WFFs), which are specific sequences of symbols that conform to the rules of a logical language.
Van Wijngaarden grammar is a type of formal grammar that was introduced by Adriaan van Wijngaarden in the 1960s. It is particularly notable for its ability to describe the syntax of programming languages in a way that is more expressive than context-free grammars, which are limited in terms of the types of constructs they can define.
The Izod impact strength test is a standardized method used to measure the impact resistance of materials, particularly plastics and metals. It is named after the engineer Edwin Gilbert Izod, who developed the test in the early 20th century. The test provides valuable information about a material's toughness and ductility, which are critical for applications where materials are subject to sudden impacts or shocks.
The Wirth–Weber precedence relationship is a concept in the field of software engineering and project management, particularly concerning the organization of tasks in software development. It is used to define dependencies between tasks and the order in which they should be executed. This precedence relationship identifies which tasks must be completed before others can begin, ensuring that dependencies are respected throughout the development process. For example, if Task A must be completed before Task B can start, then Task A has a precedence over Task B.
Program derivation is a systematic approach to software development that emphasizes the construction of programs from formal specifications. It involves a methodical transformation of high-level specifications or abstract descriptions into executable code through a series of well-defined steps or rules. This process often includes the use of mathematical reasoning and formal methods to ensure correctness and reliability.
An asynchronous system refers to a design or process in which operations do not happen at the same time or are not coordinated by a global clock signal. Instead, events occur independently and are not synchronized. This concept is prevalent in various fields, including computer science, electronics, communication, and data processing. Here are some key characteristics and explanations of asynchronous systems: 1. **Decoupling of Operations**: In an asynchronous system, components or operations can work independently of each other.
Algebraic semantics in computer science is a framework that connects the fields of algebra and formal semantics, providing a mathematical way to describe and analyze programming languages and systems. It uses concepts from algebra, such as algebraic structures (like monoids, lattices, groups, etc.), to specify the meaning of programming constructs.
Assertion Definition Language (ADL) refers to a language or set of syntactic and semantic constructs used to define assertions in various contexts, such as formal verification, software engineering, and programming languages. Assertions are statements that declare specific properties or conditions that should always hold true at certain points in a program or system. While different domains or tools may implement their own version of ADL, the primary purpose is to provide a way to specify conditions that must be met for systems to behave as expected.
Mondex is a digital payment system that was developed in the late 1990s as a form of electronic cash or digital currency. It was designed to operate in a manner similar to cash, allowing users to store and transfer value electronically, often using smart cards. The system aimed to provide a secure and convenient way for individuals to make transactions without relying on traditional banking infrastructure.
RCOS stands for the "Rochester Institute of Technology's Collaborative Open Source" initiative, which is associated with the RIT community. However, in a broader sense within computer science and software development, "RCOS" may also refer to concepts related to collaborative software development practices and open-source projects.
In computing, "retrenchment" is a formalism used in the context of software development and formal verification, particularly when dealing with changes in system requirements or specifications. It refers to a process of incrementally refining system specifications while managing the introduction of changes or the relaxation of certain requirements. Retrenchment is particularly useful in situations where it is not feasible to achieve a completely formal refinement due to various constraints, such as the complexity of the system, cost, or time considerations.
The Rational Unified Process (RUP) is a software development process framework created by Rational Software (now part of IBM) that provides a disciplined approach to assigning tasks and responsibilities within a development organization. RUP is characterized by its iterative and incremental development, which helps teams manage the complexities of software engineering projects.

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