Sir Thomas Urquhart was a 17th-century Scottish eccentric who tried to systematize a new language for trigonometry; the law of sines was abbreviated as “eproso”, which (if you know the system) encapsulates its meaning.
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.
Issue 11 of Chalkdust is out today! You can read all the articles online at http://chalkdustmagazine.com.
@esoterica A classic paper, closely related to the theory of height functions for tilings and colorings.
Conway has died.
People here might know him best for the "Game of Life", but he did so much more. The book about Conway by Siobhan Roberts is an interesting read about the man and his work.
Some will know Conway via is work on the Classification of Finite Simple Groups (with *many* others), some via his "Look and Say" sequence, while still others will know his book "Winning Ways", written with Richard Guy and Elwyn Berlekamp. My copy signed by all three is something I treasure.
Just fitted a new aerator to the tap on the bathroom sink. Now in full control of flow rate. Feel like Handy Andy crossed with a Pharaoh*.
Mathematician, koala fan, mathstodon.xyz admin,
⅓ of https://aperiodical.com. He/him
The social network of the future: No ads, no corporate surveillance, ethical design, and decentralization! Own your data with Mastodon!