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
enjoyed this release:
V/A - Lovecraft Creatures (2020)
Cian Orbe Netlabel
lovecraft, horror, dark ambient, experimental, creatures, soundtrack, ninurta, yog-sothoth, chthonian, sub-niggurath, nyarlathotep
Aha, so it doesn't seem to be set up for the `\$$…\$\$` tokens, but does work with `\\(…\\)`. OK then.
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