Linkage

“You know how the \hat command in LaTeΧ puts a caret above a letter? … Well I was thinking it would be funny if someone made a package that made the \hat command put a picture of an actual hat on the symbol instead?” And then Matthew Scroggs and Adam Townsend went ahead and did it (\(\mathbb{M}\)).

Generating 4d polyhedra from their symmetries (\(\mathbb{M}\), via), by Mikael Hvidtfeldt Christensen.

Windows on Theory and Scott Aaronson both warn about a fake web site for FOCS 2019, whose submission deadline just passed (\(\mathbb{M}\)).

GeometrieWerkstatt Gallery (\(\mathbb{M}\)). A collection of weirdlyshaped mathematical surfaces, mostly of constant mean curvature.

Sandi Irani wins IEEE TCMF Distinguished Service Award (\(\mathbb{M}\)). The award recognizes her work chairing the ad hoc committee to combat harassment and discrimination in the theory of computing community, and then getting many theory conferences to follow its recommendations.

Periodic billiard paths (\(\mathbb{M}\)). If the boundary of a given polygon is made of mirrors, these are paths that a laser beam could take that would eventually reflect back to the starting point and angle and then repeat infinitely. It remains a heavilystudied open question whether such paths exist in every triangle. This blog post from 2014 provides a proof that they do exist in polygons whose vertex angles are all rational multiples of \(\pi\).

PLOS disappears one (or maybe more) of its hosted blogs (\(\mathbb{M}\)) without any warning to the blog author, without any attempt at keeping old blog links still working, and with only a belated apology.

The Supreme Court’s math problem (\(\mathbb{M}\), via). Jordan Ellenberg explains why, in testing for gerrymandering, asking about deviation from proportional representation is the wrong question. Democratic systems naturally concentrate power to the majority rather than being proportional. The right question is whether that concentration is at the natural level, or is artificially accelerated in one direction or another.

EU falsely calls Internet Archive’s major collection pages, scholarly articles, and copies of US government publications “terrorism” and demands they be taken down from the internet (\(\mathbb{M}\), see also). The EU is about to vote to require terrorism takedowns to happen within an hour, and these requests are coming on European times when all Internet Archive employees (in California) are asleep, making manual review of these bad takedowns difficult.

SIAMACM Conference on Algorithmic Principles of Computer Systems, APOCS (\(\mathbb{M}\)). This is a new conference to be held with SODA, next January in Salt Lake City, covering “all areas of algorithms and architectures that offer insight into the performance and design of computer systems”. Submission titles and abstracts are due August 9 (with full papers due a week later) so if this is an area you’re interested in there’s still plenty of time to come up with something to submit.

Sad news from Berkeley: Elwyn Berlekamp has died (\(\mathbb{M}\), see also). Berlekamp made significant contributions to combinatorial game theory (motivated, as I understand it, by the mathematical study of Go endgames), coding theory, and algorithms for polynomials.

An unofficiallyproposed new Berlin transit map replaces stylized axisparallel and diagonal line segments with smooth curves (\(\mathbb{M}\), via). The old design was seen as “out of style”, “too robotized”, and too difficult to follow routes. There’s still a strong preference for axisparallel and diagonal lines in the new map, but the connections between them have been smoothed out.