Linkage

Statement of concern from the American Statistical Association over the Greek government’s persecution of former chief statistician Andreas Georgiou (\(\mathbb{M}\)) for (according to the ASA) producing accurate and truthful statistical reports on the Greek economy that cast disrepute on the unverifiable claims of earlier governments.

That other microblogging site has a bot specifically devoted to replacing links to pdf versions of arxiv preprints by links to the abstracts of the same preprint (\(\mathbb{M}\)). Is there something like that for mastodon? If not there should be.

For a centrally symmetric star-shaped set in the plane, each line through the center cuts its perimeter into two equal-length curves. But these are not the only shapes with this property: 18th-century Jesuit polymath Roger Boscovich observed that a heart-like shape formed by three semicircles has the same property (\(\mathbb{M}\), via).

Three correlations and a samosa (\(\mathbb{M}\), see also, see also). \(3\times 3\) symmetric matrices with unit diagonals form a three-dimensional linear space, in which the samosa is a curvy 3d convex set representing the positive definite matrices. Taking sections of it allows you to infer the possible correlations between two variables, given each of their correlations with a third.

I couldn’t resist picking up a copy of The Architecture of Trees (\(\mathbb{M}\)), a coffee-table book centered on pen-and-ink illustrations of the summer and winter forms of over 200 types of tree, on a recent visit to the Mendocino Coast Botanical Gardens (beautiful this time of year with many flowers in bloom). Some reviews: 1, 2, 3.

Dujiangyan Zhongshuge (\(\mathbb{M}\), via), bookstore in Chengdu with mirrored floors and ceilings creating the feeling of an infinite Escher palace of books.

Illustrating geometry (\(\mathbb{M}\)). An apparently-defunct blog from 2016–2017 with several interesting posts about technical illustrations in mathematics.

Which \(n\times n\times n\) grids have Hamiltonian cycles that turn at every step? (\(\mathbb{M}\)) After I linked to this, a later answer pointed to the recent book Bicycle or Unicycle？A Collection of Intriguing Mathematical Puzzles, by Stan Wagon and Daniel Velleman, which has solutions for all even \(n\) on pp. 89–96. A simple parity argument shows that it’s impossible on odd grids, but the same book conjectures that these have Hamiltonian paths except in the case \(n=3\).

Accepted papers to the International Workshop on Graph-Theoretic Concepts in Computer Science (\(\mathbb{M}\)). My paper “The Graphs of Stably Matchable Pairs” is one of them. The conference will be online June 23–25. Unlike many conferences, WG prepares the proceedings after the conference, to allow authors to incorporate feedback from presentations. Details of how to participate don’t seem to be online but I’m sure they’ll be made available soon.

Why you shouldn’t be too pessimistic (\(\mathbb{M}\)). Igor Pak on the nature of mathematical conjectures.

Two surnames, no hyphen: Claiming my identity as a Latin American scientist (\(\mathbb{M}\), via). Johana Goyes Vallejos in Science, on respect for diversity in naming styles in academia.