Cute proof of Sperner's theorem (en.wikipedia.org/wiki/Sperner%) from a talk by R. P. Stanley last Thursday: represent subsets of $[0,n-1]$ by strings of $n$ parens, ")" in position $i$ if $i$ is in the set, "(" otherwise. In each string, flip the first unmatched (, grouping the subsets into chains like (()(( – )()(( – )())( — )())). Each chain touches the middle level once, and any other antichain at most once, so the middle level is the biggest antichain.

Time for snackums

god really played me when they gave me a love of writing mathematics on chalkboards, baking, and wearing black pants

😔 just replied-all to the entire department.

I have £60 of birthday money and I want to spend it on something frivolous and mathematical. Any ideas?

Made a snowdecahedron. Not as nice as some people on the web, but still, I deserve a beer.

Does it bother anyone else that the numbers on the shapes don't correspond to their orders of rotation?

I made a new page of sliding block puzzles:
homepages.gac.edu/~jsiehler/ga

Some great mathematical "colemanballs"

eprints.maths.ox.ac.uk/104/1/b

The practice of office staff referring to colleagues by initials has claimed another victim: the wrong DS is teaching our algebra module this semester.

I miss installation programs with personality

Quit using Mendeley people!

They started encrypting your database so you cannot easily move it over to other tools any more.

That link also helps you saving your data before it's too late.

(Elsevier are a bunch of crooks, blocking interoperability one-way and not the other. Almost as bad as Google blocking uBlock for your safety...)

Recently, Bekos et al made a major breakthrough, showing that planar graphs of bounded degree have bounded queue number.

arxiv.org/abs/1811.00816

We were able to generalize this to bounded degree bounded genus graphs.

arxiv.org/pdf/1901.05594.pdf

Look at this absolute unit!

heart equation...

how do i

math

math

I've just learned about Grete Hermann, a German mathematician and philosopher, and student of Emmy Noether. She was an anti-fascist, and provided a sort-of constructive solution to Hilbert's Nullstellensatz.
en.wikipedia.org/wiki/Grete_He

you know you’ve been doing too much complex analysis & too little living in the real world when you read “homophobic” as “holomorphic”

A Mastodon instance for maths people. The kind of people who make $\pi z^2 \times a$ jokes.
Use $ and $ for inline LaTeX, and $ and $ for display mode.