Riesz-Fischer theorem by Ciro Santilli 37 Updated 2025-07-16
A measurable function defined on a closed interval is square integrable (and therefore in ) if and only if Fourier series converges in norm the function:
John von Neumann by Ciro Santilli 37 Updated 2025-07-16
This is the one Ciro Santilli envies the most, because he has such a great overlap with Ciro's interests, e.g.:
Video 1.
John von Neuman - a documentary by the Mathematical Association of America (1966)
Source. Some good testimonies. Some boring.
In economics, "regular distribution" isn't a commonly used term like "normal distribution" or "log-normal distribution," which refer to specific statistical distributions used to model data in various contexts. However, it may refer to the general concept of "regular" in the context of how resources, income, or wealth are distributed among individuals or groups in an economy. Often, regular distribution may be sought in discussions about equity and fairness in economic systems.
The shadow rate is a concept used in economics and finance to describe an implicit interest rate that reflects the monetary policy stance when traditional policy tools, like the nominal interest rate, reach their lower bound (often close to zero). In such situations, central banks may find it challenging to stimulate the economy solely through standard interest rate adjustments, leading to the implementation of unconventional monetary policies, such as quantitative easing or forward guidance.
International research institutes for mathematics refer to organizations and facilities dedicated to advancing the field of mathematics through research, collaboration, and education. These institutions often bring together mathematicians from around the world to collaborate on various mathematical problems, conduct research, and promote the dissemination of mathematical knowledge. Some notable examples of international research institutes for mathematics include: 1. **Institute for Advanced Study (IAS)** in Princeton, New Jersey, USA - A prestigious research institute that has hosted many of the world's leading mathematicians.
The Newton Gateway to Mathematics is a collaborative initiative designed to connect researchers, educators, and the general public to current mathematical research and its applications. It aims to facilitate interaction between mathematicians and a wider audience, promoting the understanding and relevance of mathematics in various fields. The initiative is often associated with the Isaac Newton Institute for Mathematical Sciences in Cambridge, UK.
In the context of programming language theory, "stubs" refer to simplified or incomplete implementations of a program or component that are used for testing, development, or educational purposes. These stubs serve as temporary placeholders for more complex code that hasn't been fully implemented yet. Here are a few key points about stubs: 1. **Purpose**: Stubs are often used in software development to isolate components for testing.

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 5. . 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.
  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