Chris Purcell @ccppurcell@mathstodon.xyz

This is inspired by the saying "anyone driving slower than me is an idiot; anyone driving faster than me is a maniac."

Anyone less fit than me is risking their life; anyone more fit than me is wasting their time.

@christianp Hey it totally slipped my mind, but the original reason I was looking up that "Seven trees in one" stuff was because I was looking at your esoterica and thought it would be a good addition! I actually forgot that was the motivation *before* writing the initial toot asking for it, and I hadn't fully twigged that you were behind @esoterica at that point (I just noticed it in local timeline)

Tautological gems of wikipedia: A function of bounded mean oscillation is [a function] whose mean oscillation is bounded. #wikipedia

https://en.wikipedia.org/wiki/Bounded_mean_oscillation

addendum: forgive me if this is wrong, but I am almost certain I have this correct.

One of the steps in the Chudnovsky-Seymour clawfree structure theorem is to prove that a connected clawfree graph containing an induced icosahedron must contain a homogeneous pair of cliques. But you can prove something better: such graphs are exactly the graphs you can get from an icosahedron by expanding some of the vertices into cliques (and adding all edges between adjacent cliques). Recreational question: which other pairs of graphs have this property? I have no idea btw.

I am looking for a paper I once read that was about trees (in graph theory). The idea was something like: All trees can be formed from two trees by adding an edge between them, so let's be silly and say that T=T²+1 or some such. The joke being, that's what a "seventeenth century" mathematician might do (or xth century for suitable x). Then the rest of the paper is a great big "aahhh but actually you can make that rigorous". Any ideas?

I've had conversations with non-mathematicians who think an $n$-dimensional space with $n>4$ (or even 3) is just absurd nonsense. But then I was thinking about stable set polytopes of graphs and graphs with at most 4 vertices are pretty trivial for us...

I have been followed by four bots in quick succession, all of whom are from the same mastodon instance, of which they are the only members... what's going on here?

I wonder what proportion of papers these days are written by authors who used sci-hub, or critically rely on other papers that were. Will/has there come a point where all research owes a debt to Alexandra Elbakyan?

My new department gave me a windows machine. Trying to set up Ubuntu on Windows (eg change the godawful color scheme). Various things involve pasting into vimrc or whatever. But terminal can't access windows clipboard! So: paste into text file in windows system, then move it with bash to the home directory, then vim, yank, :e paste. Ffeww.

I have devised the following puzzle.

Other than the number of letters, what do the words LAXATIVE and ANTIFLAK have in common?

I know antiflak isn't really a proper word, but I haven't been able to find an equivalent puzzle with a pair of proper words.

Who is falling for these fake journal emails that ask you to resubmit your papers? The latest one has Pacman shapes as bullet points and a grammatical mistake in six out of eight sentences.

I think doing mathematics and playing in the NBA are the closest human beings come to real live magic.

I first learned the handshaking lemma in 2004 I think. I have never (afair) had to refer to it directly in my research, until today! https://en.wikipedia.org/wiki/Handshaking_lemma