@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

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?

No one knows how to cite 4chan mathematicians who solved an interesting problem.

https://mobile.twitter.com/adversariel/status/1054811880919834634

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 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

Mathematician, computer scientist, bassist, knitter?

Joined Jan 2018