Hilbert's problems by Ciro Santilli 40 Updated 2025-07-16
He's a bit overly obsessed with polynomials for the taste of modern maths, but it's still fun.
Tax the rich by Ciro Santilli 40 Updated 2025-07-16
Video 1.
How the rich avoid paying taxes by Vox (2021)
Source. Features interview with Morris Pearl, a rich dude that is campaigning to tax the rich. He also participates in an association called "Patriotic Millionaires" to further this agenda.
Video 2.
What Eating the Rich Did For Japan by Asianometry (2021)
Source.
Conjecture by Ciro Santilli 40 Updated 2025-07-16
A conjecture is an open problem in mathematics for which some famous dude gave heuristic arguments which indicate if the theorem is true or false.
Hyperfine structure by Ciro Santilli 40 Updated 2025-07-16
Small splits present in all levels due to interaction between the electron spin and the nuclear spin if it is present, i.e. the nucleus has an even number of nucleons.
As the name suggests, this energy split is very small, since the influence of the nucleus spin on the electron spin is relatively small compared to other fine structure.
TODO confirm: does it need quantum electrodynamics or is the Dirac equation enough?
The most important examples:
LinkedIn by Ciro Santilli 40 Updated 2025-07-16
LinkedIn fully complies with censorship imposed locally by the Chinese government, and does so in a non-transparent way: cirosantilli.com/china-dictatorship/linkedin.
It is hard to understand what the point of that website is, as it is basically just a more closed version of Facebook, but alas, it has flourished as the only place where people post more useful content compared to Twitter and Facebook. In any case, Ciro just applies the same unfollow policy to all of them: aggressively filter your social media follows.
Cirism by Ciro Santilli 40 Updated 2025-07-16
Welcome to the wonderful world of Cirism!
Followers of Cirism call themselves Cirists, and their primary goal in life is to obtain Cirocoins.
Enlightened Cirists donate money to the cause at: Section "Sponsor Ciro Santilli's work on OurBigBook.com". It is totally optional of course, your soul will just be eternally damned if you don't.
Ciro Santilli once proclaimed:
Thou shalt eat thy watermelon in the morning, and thy melon in the evening. Thou shalt not eat thy watermelon in the evening, nor shalt thou eat thy melon in the morning.
FEniCS Project by Ciro Santilli 40 Updated 2025-07-16
One big advantage over FreeFem is that it uses plain old Python to describe the problems instead of a domain-specific language. Matplotlib is used for plotting by default, so we get full Python power out of the box!
One downside is that its documentation is a Springer published PDF link.springer.com/content/pdf/10.1007%2F978-3-319-52462-7.pdf which is several years out-of-date (tested with FEnics 2016.2. Newbs. This causes problems e.g.: stackoverflow.com/questions/53730427/fenics-did-not-show-figure-nameerror-name-interactive-is-not-defined/57390687#57390687
system of partial differential equations are mentioned at: link.springer.com/content/pdf/10.1007%2F978-3-319-52462-7.pdf 3.5 "A system of advectiondiffusion–reaction equations". You don't need to manually iterate between the equations.
On Ubuntu 20.04 as per fenicsproject.org/download/
sudo apt-get install software-properties-common
sudo add-apt-repository ppa:fenics-packages/fenics
sudo apt-get update
sudo apt-get install --no-install-recommends fenics
sudo apt install fenics
python3 -m pip install -u matplotlib
Before 2020-06, it was failing with:
E: The repository 'http://ppa.launchpad.net/fenics-packages/fenics/ubuntu focal Release' does not have a Release file.
but they seem to have created the Ubuntu 20.04 package as of 2020-06, so it now worked! askubuntu.com/questions/866901/what-can-i-do-if-a-repository-ppa-does-not-have-a-release-file

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