Four pages are indeed necessary for planar graphs: https://arxiv.org/abs/2004.07630

At STOC 1986, Yannakakis proved that planar graphs have 4-page book embeddings (see https://en.wikipedia.org/wiki/Book_embedding for what this means), announced an example requiring 4 pages, but never published the example. Finally now Bekos et al. have provided detailed constructions for planar graphs requiring 4 pages.

Still lost in limbo: Unger's claim from 1992 that testing 3-page embeddability with fixed vertex ordering is polynomial.

A variant of the classic 15-puzzle, where the puzzle is coiled around a cylinder. Unlike the original, this version is solvable because of the extra connection between the first and sixteenth squares of the frame. YouTube: https://youtu.be/rfAEgxNEOrQ

New blog post: Mathematics books by women, https://11011110.github.io/blog/2020/03/08/mathematics-books-women.html

A day's break in the #UCU strike has allowed us to open-source Coursebuilder, the tool we made to produce accessible web-based versions of lecture notes.

https://github.com/coursebuilder-ncl/makecourse

It takes in LaTeX, and outputs HTML pages and slideshows.

enjoyed this release:

https://archive.org/details/lovecraft-creatures

V/A - Lovecraft Creatures (2020)

Cian Orbe Netlabel

2020-02-14

CC BY-NC-ND

lovecraft, horror, dark ambient, experimental, creatures, soundtrack, ninurta, yog-sothoth, chthonian, sub-niggurath, nyarlathotep

testing MathJax

Aha, so it doesn't seem to be set up for the `\$$…\$\$` tokens, but does work with `\\(…\\)`. OK then.

Ed Pegg, Jr has started updating http://www.mathpuzzle.com/ again! Hooray!

Joined Jan 2020