"Possible Worlds" is a play written by Canadian playwright Robert LePage. Premiering in 1986, the play explores themes of identity, reality, and the nature of existence. The narrative often intertwines the lives of its characters with complex storytelling techniques, incorporating multimedia elements that are characteristic of LePage's work. The play typically features a fragmented structure, where characters navigate different realities and alternative life paths, challenging conventional notions of time and space.
"The Aleph" is a short story written by Argentine author Jorge Luis Borges, first published in 1945 as part of his collection titled "El Aleph." The story revolves around a man named Daneri, who has become obsessed with capturing the essence of his experiences and the universe through his poetry. The narrative also explores themes of infinity, the nature of perception, and the limits of human understanding.
A list of algebras typically refers to various algebraic structures that fall under the umbrella of abstract algebra. Algebras are mathematical systems that consist of sets equipped with one or more operations that satisfy certain properties. Here are some common types of algebras: ### 1. **Algebraic Structures** - **Groups**: A set equipped with a binary operation that satisfies closure, associativity, has an identity element, and every element has an inverse.
The term "Index of wave articles" is not a standard term in scientific literature, but it can refer to various concepts related to the indexing of articles that discuss wave phenomena in fields such as physics, engineering, or environmental science.
Lie groups are mathematical structures that combine algebraic and geometrical properties, playing a crucial role in various areas of mathematics and theoretical physics. Below is a list of topics related to Lie groups, which may serve as a guide for further exploration: 1. **Basic Definitions and Properties** - Definition of Lie groups and examples - Basic properties (smoothness, topology) - Matrix Lie groups 2.
A "fundamental theorem" typically refers to a statement that is foundational and essential to a particular area of mathematics or science. Such theorems often establish critical relationships, properties, or structures within that field. Here are a few well-known fundamental theorems across various domains: 1. **Fundamental Theorem of Arithmetic**: Every integer greater than 1 can be uniquely factored into prime numbers, up to the order of the factors.
Nichols algebras are an important class of algebra in the theory of Hopf algebras and are particularly involved in the study of quantized enveloping algebras and other structures in algebra and representation theory. A finite-dimensional Nichols algebra is a special kind of graded algebra associated with a graded vector space, equipped with a specific quadratic form. The classification of finite-dimensional Nichols algebras is a rich area of study and has been a subject of considerable research.
Numerical libraries are essential tools in programming that provide functions for numerical computing, data manipulation, and scientific calculations. Here’s a list of some popular numerical libraries across various programming languages: ### Python 1. **NumPy**: Fundamental package for numerical computations in Python. 2. **SciPy**: Builds on NumPy and provides additional functionality for optimization, integration, and statistics. 3. **Pandas**: Provides data structures for efficiently storing and manipulating large datasets.
The properties of sets of real numbers encompass a variety of concepts from topology, measure theory, and real analysis. Here is a summary of some key properties and classifications of sets of real numbers: 1. **Countable vs. Uncountable**: - **Countable Set**: A set is countable if it is finite or can be put in a one-to-one correspondence with the natural numbers (e.g., the set of rational numbers).
The Institute of Mathematics of the Polish Academy of Sciences (Instytut Matematyki Polskiej Akademii Nauk, IM PAN) is a prominent research institution in Poland dedicated to the study of mathematics. Established in 1952, it is part of the Polish Academy of Sciences, which is the nation's leading scholarly organization. The Institute's main objectives include conducting high-level research in various fields of mathematics, providing education and training for mathematicians, and promoting mathematical knowledge both in Poland and internationally.
Mathematical practice refers to the habits, processes, and reasoning that mathematicians and students use when engaging with mathematical concepts and problems. It encompasses a range of skills and approaches that enable individuals to effectively understand, communicate, and apply mathematical ideas. The concept is often associated with standards in mathematics education, such as those outlined in the Common Core State Standards (CCSS) in the United States.
An **air lock** is a controlled environment that prevents air or contaminants from entering or exiting a specific area. It is commonly used in various settings, including: 1. **Spacecraft:** Air locks are utilized in space vehicles to facilitate the transfer of astronauts and equipment between the pressurized environment of the spacecraft and the vacuum of space. An astronaut would enter the airlock, depressurize the chamber, and then open the outer door to exit into space.
The philosophy of mathematics is a branch of philosophy that explores the nature and foundation of mathematics. It examines questions regarding the nature of mathematical objects, the truth of mathematical statements, and the epistemological and existential status of mathematical knowledge. Literature in this field encompasses a wide range of topics, debates, and positions, often classified into several key areas: 1. **Ontological Questions**: This area focuses on what mathematical objects (such as numbers, sets, functions, etc.) are.
Theories of deduction are frameworks within logic that explore the principles and structures used in deductive reasoning. Deduction is a form of reasoning where conclusions follow necessarily from premises. If the premises are true, the conclusion must also be true. Theories of deduction can vary based on the systems and axioms they accept, as well as the nature of the logical operators they use.

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