Assorted links by Tyler Cowen September 2, 2011 at 7:25 am 1. The Gated City, new Kindle eSingle by Ryan Avent, on urban economics. 2. The Smile Sessions are to be released; I had my own mix tape over twenty years ago. 3. Justin Wolfers on Brookings. 4. How did Watson evolve? 5. What ever happened with the P vs. NP proof?