I have fixed up Chapter …

I have fixed up Chapter 9 of the notes quite a bit; no new material, but a polish of what was already there. And I've moved the section on convergence of the control polygon to this chapter form Chapter 4. A new version of Chapter 4 that reflects this will be out soon. On Monday I intend to lecture on Sections 9.2.3 and Sections 9.3 and 9.4.