I learned many new things from James Iry’s brief history of programming languages. For example, while I’ve used Lisp for some time now, I had no idea of how it all began:

John McCarthy and Paul Graham invent LISP. Due to high costs caused by a post-war depletion of the strategic parentheses reserve LISP never becomes popular. In spite of its lack of popularity, LISP (now “Lisp” or sometimes “Arc”) remains an influential language in “key algorithmic techniques such as recursion and condescension”

Condescension has never made my programs run faster, but it’s what makes writing them worthwhile.

I was looking for an introduction to the topic of random matrices, and I came across this survey article by Edelman and Rao on the subject. It considers a somewhat broader point of view than just results on the random distribution of eigenvalues, which are the most famous results in the subject.

One thing I found interesting is that you can explicitly calculate the Jacobian of various matrix decompositions as nonlinear functions of the matrix entries. They use this to help explain results on the random distribution of eigenvalues. More on this approach can be found in Edelman’s thesis.

This is the 5th year anniversary of this blog. The list of things I’ve managed to do for 5 years is very short, but this is one of the things on it.