I deny the fact that I just went three weeks without posting. Nothing on the Internet can be trusted, even timestamps on blog posts.
The math librarian at Drexel University, Peggy Dominy, has a blog. Most of the posts are about acquisitions by Drexel’s library, but some are about new public math resources. For example, from this post I learned that the Hiroshima Mathematical Journal is now open access.
When I first took abstract algebra, I loved theorems classifying all of the groups of a certain order. Here is a paper I would have loved, The Groups of Order Sixteen Made Easy. Normally, the classification of groups of order 16 is described in terms of group extensions and the theory of p groups. The author bypasses all that to give a more elementary derivation.
Via God Plays Dice.
This is a test post to see what’s involved in uploading images.
This is of course the Sierpinski carpet. What’s interesting to me is that many objects that, in a previous age dominated by a picture of the physical world as a continuum, seemed deeply pathological, have straightforward computer-language descriptions. For example, you can check whether or not a point in the plane is on the Sierpinksi plane by looking at the ternary expansion of its coordinates, which is a couple of lines of computer code. From the point of view of the computer, the Sierpinksi carpet is not much more complicated than a parabola. I suspect that the popularity of fractals marks a change in the popular imagination of the dominant metaphor for mathematics, from mathematics as mechanics to mathematics as computer program.