Linkage from Japan

World guidebook for mathematical tourism (in Spanish). Too bad there are no entries for Tokyo, where I am as I post this.

What is the least symmetric triangle in the plane? (G+, via). An answer can be obtained by constructing a certain arrangement of great circles on the unit sphere and finding a point of the sphere that is farthest from any great circle.

Tardos function (G+). New Wikipedia article on the function used to poke holes in Norbert Blum’s claimed proof of \(\mathsf{P}\ne\mathsf{NP}\).

Titokowaru and Te Whiti discuss the question, ‘What is Peace?’ (G+). New Zealand lithographer Marian Maguire mixes Māori and ancient Greek art styles in a dialogue on war, peace, and passive resistance between Socrates and Māori leader Tītokowaru.

Participants in a Thai academic conference arrested for violating public-assembly laws. Relevant for ISAAC, this December in Phuket, Thailand?

Why a Dutch court stopped high school students from exchanging schools (G+), and how the mechanism used to allocate scarce resources can have a big effect on how the participants behave.

Bubble painting (G+). What you get when you make a foam of bubble bath solution and paint, spread it on paper, and then let the bubbles dry and pop.

For a democratic society to remain democratic, it must reject democratically chosen acts whose effects are inimical to democracy. Suresh Venkatasubramanian uses Popper’s Paradox of Tolerance (for a tolerant society to remain tolerant, it must be intolerant of intolerance) as an argument against partisan gerrymandering.

Paper model of the Villarceau circles on a torus (G+, via).

Mysteries of turbulence unravelled (G+). Simulations follow how swirls in a fluid transfer and dissipate energy.

A biology preprint exchange from the early 1960s (G+), killed off by publishers banning shared papers from being published.

Kyouhei Kasai, Tokyo instagrammer. While in Japan I saw a tiny gallery exhibit of some of his film work.

Braids in higher dimensions (G+). One-dimensional curves cannot form nontrivial braids in four dimensions, but two-dimensional surfaces can. Zsuzsanna Dancso explains how to visualize these in one-dimension lower, by interpreting the braiding dimension as time.

Separating fact from speculation in math history (G+). Evelyn Lamb clears up some of the nonsense and hype surrounding Wildberger’s new paper on Babylonian tablet Plimpton 322.

Edge-to-edge Heesch numbers (G+). Craig Kaplan finds pentagons that can be surrounded by edge-to-edge copies of themselves but cannot tile the whole plane.