This is a list of links to things I find interesting.


A blog series on the classical theorem of multivariable calculus.

A blog post with a proof of the Abel-Ruffini theorem. Complete with javascript group actions.

A blog post by Terence Tao.

A blog post by Scott Aaronson.

Using computers to generate numerical conjectures. My favorite is

    \[-\frac 4\pi =-1+\frac 1{-3+\frac 1{-3+\frac 4{-5+\frac 9{-7+\frac {16}{\dots}}}}}\]

This is very difficult to explain. Anyway, it’s a great explanation of what mathematics is, what axioms are, etc.

Twofold performance increase on the greatest common divisor operation by using the binary variation of Euclid’s algorithm.

The probability of ending up with a single coin when you start with n and toss them and discard the tails.

The highlight of this post is the identity

    \[\sigma_7(n) = \sigma_3(n) + 120\sum_{m=1}^{n-1}\sigma_3(m)\sigma_3(n-m).\]


A blog series defending a tentative theory that the obesity epidemic is caused by environmental contaminants.

A collection of courses which attempts to teach physics concepts with the minimum amount of overhead.

A derivation of the Boltzmann distribution (of the density of the atmosphere versus height) in a not handwavey way.

  • Saving the earth from the Sun’s red giant phase

A game about an universe where you can run at light speed. It’s great for building intuition about relativistic phenomena.


A graph of the S&P 500 Shiller PE since 1872.

The source of that data, Shiller himself.

Aswath Damodaran investigated the motives for China’s recent crackdown on its tech companies.


  • Earth and Stars – Thomas Pesquet

Picture taken aboard the International Space Station.

Earth and stars


A podcast series on the history of Rome, from its founding to the fall of the Western Empire. In astounding detail.

Orwell ponders about the consequences of the then new atomic bomb technology. This also explains something I always found unclear in 1984: why is it that the world is divided into superstates? Wouldn’t an autocracy of many conventional sized states be as plausible? In his words “we have before us the prospect of two or three monstrous super-states, each possessed of a weapon by which millions of people can be wiped out in a few seconds, dividing the world between them”.

A project that makes exhaustive lists of war related things, notably a list of all the wars between 1816 and 2007.

Successful bioterrorism attack.


Measurements of the latency of several computers and phones.


A university decided to do the obvious and minmax their ranking.