Infinite Napkin by Ciro Santilli 37 Updated 2025-07-16
800+ page PDF with source on GitHub claiming to try and teach the beauty of modern maths for high schoolers. Fantastic project!!!
An adjacency matrix is a square matrix used to represent a finite graph. It indicates whether pairs of vertices (or nodes) in the graph are adjacent (i.e., connected directly by an edge) or not. Here's how it works: 1. **Matrix Structure**: The size of the adjacency matrix is \( n \times n \), where \( n \) is the number of vertices in the graph. Each row and column of the matrix corresponds to a vertex in the graph.
David Fowler is a mathematician known for his work in the field of mathematics education, as well as for his contributions to research in various areas of mathematics. While there may be many individuals with that name in the academic community, one notable David Fowler is recognized for his efforts in improving mathematics teaching and learning through his research and writings.
David Manolopoulos is not a widely recognized figure in popular media or historical contexts, so it is possible that you are referring to a specific individual who may have a local or niche relevance. Without additional context, it is difficult to provide an accurate description or significance of David Manolopoulos.
David Reitze is an American physicist known for his work in gravitational wave astronomy and laser physics. He has been involved with major experiments such as LIGO (Laser Interferometer Gravitational-Wave Observatory), which made the first direct detection of gravitational waves in 2015. Reitze has held various leadership roles in the scientific community, including serving as the executive director of the LIGO Laboratory.
A quasitoric manifold is a type of manifold that can be described as a generalization of toric varieties. More precisely, quasitoric manifolds are smooth, even-dimensional manifolds that admit a smooth action by a torus (usually denoted as \( T^n \), where \( n \) is the dimension of the manifold) and have a specific relationship with combinatorial data represented by a simple polytope.
In ballistics, "deflection" refers to the alteration in the trajectory of a projectile, usually as a consequence of external factors such as wind, intermediate obstacles, or the curvature of the Earth. The term can also refer to the change in the path of a projectile after it strikes an object or surface.
As of my last update in October 2023, there is no widely recognized figure, concept, or term specifically known as "Demetrios Magiros" in major historical, cultural, or contemporary contexts. It’s possible that this name refers to a private individual or a less well-known person. If you could provide more context or clarify the area (e.g., history, geography, arts, etc.
Racah polynomials are a family of orthogonal polynomials that arise in the context of quantum mechanics and algebra, particularly in the study of angular momentum and the representation theory of the symmetric group. They are named after the physicist Gregorio Racah, who introduced them in the context of coupling angular momenta in quantum physics. ### Properties and Characteristics 1.
Donald Huffman is known for his work in the field of computer graphics, specifically as one of the pioneers of algorithms used in rendering and image processing. He is particularly known for the development of the **"Huffman coding"** algorithm, which is a lossless data compression algorithm used widely in various data encoding applications. Huffman coding assigns variable-length codes to input characters, with shorter codes assigned to more frequently occurring characters, thus reducing the overall size of the data.

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