US Department of Homeland Security decides to require foreign students in the US to either attend in-person classes or leave the country: https://www.ice.gov/news/releases/sevp-modifies-temporary-exemptions-nonimmigrant-students-taking-online-courses-during, via https://news.ycombinator.com/item?id=23751931

Or to put it another way, they are pressuring US universities into opening up in-person classes despite the ongoing pandemic, using the threat of taking away all of their foreign students.

Here's a nice puzzle, with a nice solution: http://datagenetics.com/blog/june122020/index.html

#Statistics #MachineLearning #DataScience

I enjoy an entertaining README.

“Scientific publications are too dry. Too much math, too little emotions. Science needs emojis! Leave a small heart to value the hard work gone into a paper (Smith, 2014 heart ). Flag self-citations as in (Sixt et al., 2019 selfie) Finally, you can express what you truly think directly as in (Wakefield et. al, 1998 facepalm). We could also indicate, how thoroughly we read papers (Van Wesel et al., 2014 see_no_evil)”

— https://github.com/berleon/emojicite

Asking my mathsy people ...

An odd prime is the sum of two squares iff it's 1 (mod 4).

That means that 29 (say) factors in C.

There exists a square root of -1 mod p iff it's 1 (mod 4) (Again, limited to odd primes).

That means that 29 (say) factors non-trivially mod 41 (say).

These are all clearly related, and there are connections to be had, some obvious, others likely less so.

Does anyone know of a good article that gives a feel for what's happening?

https://stats.stackexchange.com/questions/185507/what-happens-if-the-explanatory-and-response-variables-are-sorted-independently

Volumes of projections of unit cubes, Peter McMullen, Bull LMS 1984, https://doi.org/10.1112/blms/16.3.278

A cute theorem that deserves to be better known: if you hold a unit cube in the noonday sun, at any angle, its shadow's area equals its height (elevation difference between lowest and highest point). It follows immediately that the biggest possible shadow is a hexagon with area = long diagonal length = \(\sqrt{3}\), and the smallest shadow is a unit square. Similar things happen in higher dimensions.

Kind of far-fetched, but hey: years ago I saw a web page which was plain HTML (ie. without CSS), and step by step it was turned into something beautiful and readable with a few CSS rules (adding margins, increasing font size, that kind of basic typography stuff). I seem to recall it was meant to teach both basic CSS and basic typography.

Does anyone have a link or remember anything about the title or the author, so I can find it? I just find random CSS tutorials.

Boosts welcome/encouraged!

Amazing video: how to cheat at a Battleships-like game in Zelda Wind Waker. Featuring a tool developed by speed runners that uses knowledge of the pseudo-random number generator in the game, probability distributions, and deliberately losing the first game. https://youtu.be/1hs451PfFzQ

The Conway knot is not slice: Lisa Piccirillo, Ann. Math., https://doi.org/10.4007/annals.2020.191.2.5

With a recent overview of the significance of the result (if not much of its detail) in Quanta: https://www.quantamagazine.org/graduate-student-solves-decades-old-conway-knot-problem-20200519/

- website
- https://bmreiniger.github.io

Combinatorist (esp. graph theorist) turned Data Scientist

Joined Jun 2017