Ethical issues in large-corpus natural language processing, or what's behind the research that got Timnit Gebru kicked out of Google:


Geometry strikes again: (Branko Grünbaum, in Math. Mag. 1985, via

Somehow I don't think I'd encountered this short paper before but it's filled with many examples of horribly-drawn mathematics, one in the logo of the MAA. Worth reading as a warning for what not to do. Also for clear instructions on how to draw regular icosahedra correctly.

Complete classification of tetrahedra whose angles are all rational multoples of \(\pi\):, via

The original paper is "Space vectors forming rational angles",, by Kiran S. Kedlaya, Alexander Kolpakov, Bjorn Poonen, and Michael Rubinstein

3d-printed models of the chaotic attractors from dynamical systems: (Stephen K. Lucas, Evelyn Sander, and Laura Taalman in the cover article of the latest Notices)

The Place of Blogs in the Modern Math World: Katherine Thompson, Notices of the AMS,

"Clearly, mathematicians are using blogs. ... And yet despite all of the work that goes into blogs, the mathematical community has no idea what to make of them—even at the most basic level like citation."

Some tips for avoiding sexist language when writing about women:

(This is from 2015, when singular "they" was more controversial, and mostly aimed at Wikipedia editing, but it was recently reprinted in the Wikipedia Signpost, and I think it is still topical more generally.)

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I asked students to define some special categories of hexagons and invent names for them. Some excellent submissions so far include the families of Squashagons, Boltagons, Extremely Irregular Hexagons, and Treeah Stars. (I'll leave it to the reader to imagine the definitions)

Comparison of six ways to get your old Java applets running again on the modern web:, via

I have a couple of old defunct ones that I'm tempted to try this on...

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Euclidean construction of the four common mathematical means of two scalars (a,b).

A=Arithmetic mean, G=Geometric mean, H=Harmonic mean, Q=Quadratic mean (also known as Root mean square) improves accuracy of OCR and compression of PDF on its huge collection of old scanned printed documents by switching to open-source software:

A paradox, and where it led:

Peter Cameron looks at the inclusion graphs of countable models of not-well-founded set theories. The well-founded ones are all the Rado graph, but without foundation the results are more varied.

Scientists Uncover the Universal Geometry of Geology (Quanta):

This is all a bit mystic and breathless and woo, but what it really seems to boil down to is that if you subdivide space by randomly recursively splitting by planes (like a 3d Gilbert tessellation, then the average number of sides per bottom-level polyhedron is six.

YouTube no longer an acceptable platform for course lecture or academic talk content:

Unless, of course, you and your university are comfortable with your students or other audience members being subject to advertisements that interrupt the lectures and are beyond your control both in their placement and content.

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This #map shows the percentage of #female #researchers in Europe.
Germany, France and Netherlands have the lowest share of female researchers. It seems that they can learn from Albania, N. Macedonia and other Balkan nations how to reach "European standards".

Here's an amusing if minor repeated typo in the literature: "appiled superconductivity", (177 hits). I think the source is IEEE, which spells Trans. on Applied Superconductivity correctly on its site but misspells it repeatedly in the doi database. So if you get your citations from doi metadata, you will get this error.

You can see the metadata for a doi by doing curl -LH "Accept: application/x-bibtex" on the url for the doi. Try e.g. 10.1109/TASC.2005.849553

Contortion engineering:

Engineering-style drawings of Escher-like impossible objects. An old link from my old Geometry Junkyard site — its old earthlink url went dead some time after 2016, when last captured it, but now it has a new home.

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