As of today the course is up through Part 30, which gets us most of the way through Handout 8. (Note: I edited Handout 8 a bit to streamline it and move some technicalities to the To-Do List–which we will turn to eventually!) The big news is we are now through the proof of (a somewhat restricted version of) Duhamel’s Principle. The proof is almost trivial once we’ve set up the machinery, but in Handout 9 we’ll look carefully at a pretty fundamental issue that we’ve glossed over so far. After a bit more with the story of distributions and convolutions we’ll switch gears a bit to Fourier.