Linkage

You can find plenty of online stories celebrating the release into the public domain of Winnie the Pooh (text, not film), Hemingway’s The Sun Also Rises, etc. But the situation for Ludwig Wittgenstein is more complicated. All his own writing is now public domain in life+70 countries, but the work of later editors might not be. Michele Lavazza explains (\(\mathbb{M}\), via).

Math rock (\(\mathbb{M}\), via), Jordi Lefebre.

Free abelian group (\(\mathbb{M}\)), now a Good Article at Wikipedia. This concept may seem trivial at first, wrapped in unnecessary formalism. But these things come up in a lot of seeminglyunrelated contexts: multiplication of rational numbers, addition of integer polynomials, lattices in the geometry of numbers, chains in homology theory, and divisors in algebraic geometry. I worried that its technicality might make it hard to pass GA but fortunately I got a sympathetic reviewer.

Quantum graph theory (\(\mathbb{M}\)): what happens when qubits have pairwise entanglements described by some graph? And which graphs can be transformed into each other by local quantum operations? Ken Regan explains.

Giant weeble in a Budapest plaza (\(\mathbb{M}\), via): it wobbles but it won’t fall down. But unlike the childhood toy, it does it despite being of uniform density, because of its special shape, rather than by having a much denser weight near one end. It’s theorized that tortoises have evolved a similar shape so that they can automatically right themselves. For more mathematical details, see Gömböc on Wikipedia

Dictionary of mathematical eponymy: The Laves Graph (\(\mathbb{M}\)). I did a lot of work in 2014 on this topic in Wikipedia, but it evidently needs more editing for accessibility. I did not know the part about Laves being sent to the army because the Nazis viewed him as sympathetic to Jews, and then pulled into a secret project to develop unobtanium for Göring, guarded by an alchemist who helpfully insisted on adding lizard bones to the alloys and dangling crystal spheres over them.

Our quarter started this week, online through Zoom, accessed in Canvas (\(\mathbb{M}\)). To set it up I have to:
 Find and navigate to another site in which I can request a Canvas site, but get redirected to the campus login page, where I have to handtype my name and password, then get to a page to choose my twofactor authentication, select the phone option on that page, find and unlock my phone, and find and approve the twofactor authentication request on my phone
 Back at the site to request a Canvas site, use it to actually request a Canvas site; this does not actually create the site, but rather puts it into a queue to be processed one or two hours later
 Once the site is created, navigate to Canvas, going through all the same campus login steps first.
 Search the web for the campus page on how to enable Zoom, because the steps to do so are not simple or obvious enough to remember, and neither is the location of the campus page.
 Follow the five nonobvious steps on that page for adding Zoom to a Canvas site.
 Go to the new Zoom tab of my new Canvas site where I still have to go through all of the usual Zoom things to schedule a meeting that repeats weekly but only for some of the weekdays (many more steps).
Someone else in the discussion said that to manage their online classes they have to go through seven different web sites; my count is not nearly that high. Whatever happened to the science of userfriendly interfaces?

An early look at the impact of the Chinese Academy of Sciences journals warning list (\(\mathbb{M}\)). The CAS list does not seem helpful as a tool for identifying specific journals as predatory, because it lists so few, and one has to filter for political motivation, but maybe it can still find patterns of bad publishing practices. I wasn’t particularly surprised to see MDPI and Hindawi high on their hit list, but the presence of a major IEEE journal (IEEE Access) was more interesting.

The new web site of the journal Ars Combinatoria (\(\mathbb{M}\)), after the old site got taken over by gambling spammers. Thanks to Jannis Harder for finding it for me by tracing through DNS history and trying its old IP address; it wasn’t coming up on searches and I wouldn’t have thought of doing that. Despite being found again, the journal may be in trouble: MathSciNet doesn’t list anything from them in 2021 and the new site says that as of December 2021 the entire editorial board has resigned (with no explanation other than “ask the publisher”).

Short video of curvefolded squishable paper helix by Richard Sweeney (\(\mathbb{M}\), via). Sweeney, previously.

The insidious corruption of open access publishers (\(\mathbb{M}\)): Igor Pak looks at predatory publishing and MDPI through a deep examination of MDPI’s journal Mathematics. Ultimately he concludes that it is not actually a predatory journal, but that doesn’t mean that he thinks it is doing good work. Instead, he favors diamond openaccess and in particular arXivoverlay journals.

Colorful geometric designs for pasta interact interestingly with the pasta’s intricate shapes (\(\mathbb{M}\)), by David Rivillo.

Typical incoherence from Quanta’s attempts at making mathematics accessible (\(\mathbb{M}\)): “the Riemann hypothesis says that the Riemann zeta function equals zero whenever the real part of \(s\) equals \(\tfrac12\)”. No. No, it doesn’t. Fortunately they fixed it quickly. The actual result in question concerns proving betterthantrivial growth rate on the critical line of \(L\)functions; see “Bounds for standard \(L\)functions”, Paul D. Nelson, arXiv:2109.15230.

An unconstructable still life in Conway’s Game of Life (\(\mathbb{M}\)). The configuration shown in the link is stable (if its boundary is stabilized appropriately) but, if it appears in any pattern, it must always have been that way, in all predecessors of the pattern. As such, it answers the question “can every still life be constructed by gliders?” negatively.

PopUp Geometry: The Mathematics behind PopUp Cards (\(\mathbb{M}\)), new book by Joe O’Rourke, to appear this year. The link goes to Joe’s web site for the book. I haven’t yet seen the actual book, but it looks likely to be very interesting.