JimPropp

(2/2) “I appreciate Stephen Witt shining a spotlight on matrices, which deserve more attention today than ever before: they play important roles in ecology, economics, physics, and now artificial intelligence ("Information Overload", November 3). But Witt errs in bringing Hardy's famous quote ("there is no permanent place in the world for ugly mathematics") into his story. Matrix algebra is the language of symmetry and transformation, and the fact that a followed by b differs from b followed by a is no surprise; to expect the two transformations to coincide is to seek symmetry in the wrong place—like judging a dog's beauty by whether its tail resembles its head. With its two-thousand-year-old roots in China, matrix algebra has secured a permanent place in mathematics, and it passes the beauty test with flying colors. In fact, matrices are commonplace in number theory, the branch of pure mathematics Hardy loved most.”

It’s used by X-ray technicians to take an X-ray that shows your fingers individually from the side, as you rest your hand on it with your fingers splayed. I doubt that this polytope has been studied, but it is definitely chiral in both the mathematical and etymology senses.

@robinhouston@mathstodon.xyz It’s small enough and light enough to carry in one’s hand.

The first half is a mathematically correct discussion of models of growth (exponential vs. logistic) in a fictional context. The second half uses the same scenario to show that sometimes there are more important things than being mathematically correct.

Of course, I’m not satisfied with five. Can anyone suggest a sixth source of “hexagons in the wild” here? The parking garage at Kendall Square Cinema tempted me, but it’s kind of a stretch to say it’s in-and-around Harvard Square.