Counting rods are a historical counting tool used in ancient civilizations, particularly in China, to perform arithmetic operations and keep track of numbers. They consist of a series of rods, typically made of bamboo or other materials, that were used in conjunction with a counting board or surface marked with specific lines or grids. The counting rods allowed users to represent numbers in a visual and tactile manner.
The Law of Excluded Middle is a principle in classical logic that states that for any proposition \( P \), either \( P \) is true or its negation \( \neg P \) is true. In formal terms, it can be expressed as: \[ P \lor \neg P \] This means that there is no third option or middle ground between a statement being true and it being false.
It seems there might be a slight misspelling in your query, as "Adriano Garsia" does not appear to correspond to any widely recognized figure or term. You might be referring to "Adriano Garcia," but without additional context, it is challenging to identify who or what you mean.
In mathematics, localization is a technique used to focus on a particular subset of a mathematical structure or to analyze properties of functions, spaces, or objects at a certain point or region. The concept is prevalent in various areas of mathematics, particularly in algebra, topology, and analysis.
Lauren Williams is an American mathematician known for her work in the fields of combinatorics, algebraic geometry, and representation theory. She has made significant contributions to the study of various algebraic and geometric structures, including the study of matroids, symmetric functions, and Schubert calculus. Williams has also been recognized for her work on problems related to combinatorial algebra, including connections between algebraic geometry and combinatorial structures.
Graphs and combinatorics are interconnected fields of mathematics that study structures and arrangements, often with applications in computer science, optimization, and other areas. ### Graphs A **graph** is a collection of nodes (or vertices) connected by edges. Graph theory is the study of these graphs and their properties.
Azerbaijani astronomers refer to individuals from Azerbaijan who have made contributions to the field of astronomy, either through research, education, or public outreach. Azerbaijan has a rich history of astronomical study, dating back to ancient times, and continues to foster interest in the field. One notable figure in the history of Azerbaijani astronomy is Nasir al-Din al-Tusi (1201–1274), a Persian polymath whose work influenced astronomy in the region.
A photon sphere is a theoretical area in the vicinity of a black hole or another massive object where gravity is strong enough that photons (light particles) can orbit the object in unstable circular paths. This occurs at a specific radius, known as the photon sphere radius, which is typically located at 1.5 times the Schwarzschild radius of a non-rotating black hole.
The Maximum Cut (Max Cut) problem is a well-known problem in combinatorial optimization and graph theory. It involves a given undirected graph, where the goal is to partition the set of vertices into two disjoint subsets in such a way that the number of edges between the two subsets is maximized.
Intermediate-mass black holes (IMBHs) are a class of black holes that are thought to have masses ranging from about \(100\) to \(100,000\) times the mass of our Sun (or \(10^2\) to \(10^5\) solar masses).
Scientific computing researchers are professionals who specialize in developing and applying computational methods and algorithms to solve complex scientific and engineering problems. This interdisciplinary field combines techniques from mathematics, computer science, and specific domain knowledge to create models, simulations, and analyses that can provide insights into physical, biological, or social systems. Key areas of focus for scientific computing researchers include: 1. **Numerical Methods**: Developing algorithms for numerical approximations of mathematical problems, including differential equations, optimization, and linear algebra.
Computational audiology is an interdisciplinary field that applies computational methods and techniques to understand, model, and improve hearing and auditory processes. This area of study combines principles from audiology, engineering, computer science, signal processing, and data science to analyze auditory data and develop innovative solutions for hearing impairments and related disorders.
Roger Peng is a statistician and data scientist known for his work in the field of data analysis, particularly related to environmental data and statistical computing. He is a professor at Johns Hopkins University in the Department of Statistics and the Whiting School of Engineering's Data Science program. In addition to his academic work, Roger Peng is also recognized for his contributions to the data science community through his online presence.
Polynomial long division is a method used to divide one polynomial by another polynomial, similar to the long division process used with numbers. It involves a systematic way of dividing polynomials, which results in a quotient and, in some cases, a remainder.
In the case of indel mutations (see limits of gel electrophoresis for minimal size difference issues), it is possible to determine the allele with gel electrophoresis. You can just read out the alleles right in the gel. It is a thing of beauty.
As of 2020, this method appears to be much cheaper than DNA sequencing approaches.
Video 1.
Gel Electrophoresis to Determine Genotype
. Source.
Paris by Ciro Santilli 40 Updated 2025-12-13
Ciro Santilli lived in Paris for a few years between 2013 and 2016, and he can confirm the uncontroversial fact that "Paris is Magic".
Not just one type of magic though. Every quarter in Paris has its own unique personality that sets it apart and gives it a different mood.
Ciro knows Paris not from its historical facts, but from the raw feeling of endless walks through its streets in different times of the year. Ciro is a walker.
Maybe one day Ciro will expand this section to try and convey into words his feelings of love for the city, but maybe the effort would be pointless. Maybe such feelings can only be felt by other free-roaming walker souls living in the city, and that is both beautiful and a shame.
Ciro had written the following in the past before he lived in smaller cities, started cycling and joined the Street reclamation movement he thought:
Paris is a friendly city to walkers, as it is not too large, and does not have too many extremely busy roads, you can basically cross all of it on foot.
Perhaps compared to São Paulo City, which is what he knew before that was true. But no, his standards have improved since. Paris has way too many cars. The noise of internal combustion engine vehicles is extremely annoying. And because there are too many personal vehicles, cars have to horn a lot to fight for space. Fuck cars. Paris has been making a big cycling push in the early 2020's, and that is great. But it is still far, far from good.

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