A Möbius transformation (or linear fractional transformation) is a function defined on the complex numbers that has the general form: \[ f(z) = \frac{az + b}{cz + d} \] where \(a\), \(b\), \(c\), and \(d\) are complex numbers, and \(ad - bc \neq 0\) to ensure that the transformation is well-defined (i.e., it is not degenerate).
In projective geometry, a **spread** refers to a specific type of geometric configuration. More formally, a spread of a projective space is a set of lines such that any two lines in the set intersect in a single point—essentially, it is a collection of lines that are pairwise distinct but share points as intersections. To provide a further context, consider a projective space over a division ring.
The aerospace industry is a global sector, and businesspeople within it come from various nationalities. Here's an overview of significant countries involved in aerospace and some key players by nationality: 1. **United States**: - Major companies include Boeing, Lockheed Martin, Northrop Grumman, and Raytheon. Many prominent aerospace executives and business leaders are American.
Aerospace architecture is a specialized field that focuses on the design and development of aircraft, spacecraft, and other aerial vehicles, addressing both functional and aesthetic aspects. It combines disciplines from aerospace engineering, architecture, industrial design, and systems engineering to create structures that are not only technically sound but also enhance the user experience.
Astronautics is the branch of science and engineering that deals with the design, development, and operation of spacecraft and the technology associated with space travel. It encompasses a wide range of activities and disciplines including, but not limited to, aerospace engineering, astronaut training, space system design, orbital mechanics, propulsion systems, and mission planning.
"Border rivers" refer to rivers that form part of the boundary between two or more countries, states, or regions. These rivers often serve as natural demarcations that define political and administrative borders. In some cases, they may also play significant roles in trade, transportation, and resource management for the areas they flow through. Examples of notable border rivers include: 1. **Rio Grande** - Forms part of the border between the United States and Mexico.
Cross-border races typically refer to competitive events that take place across the borders of different countries. These events can include various types of races, such as running, cycling, motor racing, or other sporting competitions that involve crossing into neighboring countries. For example, a cross-border running race might start in one country and have participants complete a course that leads them into another country.
The term "eponymous border lines" is not widely recognized in literature or geography, which suggests that it may refer to specific contexts or usages in niche fields. However, the term can be broken down into its components: 1. **Eponymous**: This term refers to something named after a particular person, often the founder or notable figure associated with a specific place, concept, or entity.
"Mobilities" refers to the study of the movement of people, objects, and ideas in various contexts. It encompasses a wide range of disciplines, including sociology, geography, urban studies, and transportation research. Mobilities can involve physical movement, such as travel and migration, as well as the flows of information and capital in a globalized world.
A non-renewable resource is a natural resource that cannot be reconstituted or regenerated at a sustainable rate relative to its consumption. These resources exist in finite quantities and can be depleted over time. The most common examples of non-renewable resources include: 1. **Fossil Fuels**: This category includes coal, oil, and natural gas, which are formed from the decomposed remains of ancient plants and animals over millions of years.
A rotation map is a function that describes the process of rotating points or vectors in a mathematical space, typically in two or three dimensions. In 2D space, for example, a rotation map takes a point represented by coordinates \((x, y)\) and rotates it by a certain angle \(\theta\) around the origin.
The Turán graph, denoted as \( T(n, r) \), is a specific type of graph used in extremal graph theory, which studies the conditions under which graphs contain certain subgraphs. The Turán graph is designed to be the largest \( K_{r+1} \)-free graph (a graph that does not contain a complete subgraph of \( r+1 \) vertices) with \( n \) vertices.
In graph theory, the **strength** of a graph typically refers to a specific concept related to the robustness or resilience of a network. However, the term can also have different meanings based on context. Here are a couple of interpretations: 1. **Graph Strength in Terms of Connectivity**: In some contexts, the strength of a graph can refer to its connectivity, specifically the minimum number of edges that need to be removed to disconnect the graph. This is often related to the concept of edge connectivity.
Amazon Neptune is a fully managed graph database service provided by Amazon Web Services (AWS). It is designed to support graph-based applications and can handle both property graph and RDF (Resource Description Framework) data models.
Blazegraph is a high-performance graph database that is designed to handle large-scale graph data and complex queries. It supports the RDF (Resource Description Framework) and SPARQL (SPARQL Protocol and RDF Query Language) standards, making it suitable for applications that involve semantic web technologies and linked data. Blazegraph is often used for applications such as knowledge graphs, social networks, and recommendation systems.
The Newick format is a way to represent tree structures, particularly phylogenetic trees, in a textual form. It uses a nested, parentheses-based notation that allows the representation of hierarchical relationships among various entities, such as species or genes, in a succinct manner. Each node in the tree can represent a taxon (e.g., a species) or a clade (a group of taxa), and the branches indicate evolutionary relationships.
"Shallow minor" is not a standard term widely recognized in music theory or other disciplines. However, the phrase could be interpreted in a few ways depending on the context in which it's used: 1. **Musical Context**: If we're discussing music, it might refer to a minor key (like A minor, B minor, etc.) that feels less intense or lacks depth, possibly due to its simplicity in composition or harmony.
The term "carving width" can refer to different contexts depending on the field, but it is most commonly associated with skiing and snowboarding. In this context, carving width typically refers to the width of a ski or snowboard that allows for effective carving turns. A wider carving width can offer greater stability and better edge control when making turns on hard-packed or icy conditions.

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