Linkage

Nature on National Science Foundation terminating hundreds of grants and planning for massive budget cuts (\(\mathbb{M}\)). Terence Tao writes “this is going to be hugely disruptive … and in conflict with the congressional authorization of funds appropriated for the NSF”.

A robot that unknots knots (\(\mathbb{M}\)). Not a real robot, but a thought experiment about a robot that “walks along a knot once on a knot diagram and switches every undercrossing it meets, stopping when it comes back to the starting position”. The result is always the unknot. New arXiv preprint by Connie On Yu Hui, Dionne Ibarra, Louis H. Kauffman, Emma N. McQuire, Gabriel Montoya-Vega, Sujoy Mukherjee, and Corbin Reid.

Klein bottle linocut by Ele Willoughby in honor of Felix Klein’s birthday. The yellow-green color gradient is not there only to look pretty and convey the idea of green glass, but also to indicate the position of the surface in a fourth dimension that allows it to avoid self-intersection.

“Mathematician solves algebra’s oldest problem using intriguing new number sequences”. Long thread on the latest Wildberger hype, with some curiosity about how Wildberger’s ultrafinitism lets him simultaneously believe in power series solutions to polynomial equations and disbelieve in their special case, the decimal representation of irrational roots. Meanwhile, Wildberger’s coauthor has apparently published a YouTube video noting that the mathematics described in their work was already known to Newton.

Two cartograms from the 1906 UK General Election, showing each district as a grid square, on display at Bromley House Library.

Lance Fortnow tries to classify \(\mathsf{P}\) vs \(\mathsf{NP}\) crankery (\(\mathbb{M}\)). He also suggests asking an LLM to be critical of your crank proof before showing the world, but I’m skeptical whether that’s a useful exercise: the main thing we’ve learned about LLMs is that they’re very good at telling you what you want to hear.

HalvarFlake asks for books on the geometry of high-dimensional polytopes. The two suggestions in the replies so far are Ziegler’s Lectures on Polytopes and Grünbaum’s Convex Polytopes.

Physics for Synnoets. Ben Recht on George Forsythe’s foundational vision of computer science.

Square circle. Dave Richeson 3d-prints letters that read “square” from one direction and “circle” from another, and shows them both simultaneously with angled mirrors.

The fascinating world of \(2\times 2\times 2\) tensors: its geometry and optimization challenges (\(\mathbb{M}\)). New expository article by Gabriel H. Brown, Joe Kileel, and Tamara G. Kolda.

European Mathematical Society statement defending academic freedom in mathematics (\(\mathbb{M}\)).

3d-printed Reuleaux triangle bolt with square nut (\(\mathbb{M}\)).

New pope is a mathematician (\(\mathbb{M}\)), the second after Sylvester II. Or at least, he was an undergraduate mathematics major.

One of my former doctoral students, Nil Mamano, is coauthor on a recent book, Beyond Cracking the Coding Interview (\(\mathbb{M}\)). I don’t know much more about it than what you can see on the web site and at a reddit thread about it, but it looks like an interesting and useful resource for people approaching this hurdle. (The reason I found out about it: Nil found a typo in one of my blog posts that he cited in the book. Please do tell me about such things! I’m happy to correct old mistakes.)