On page 1, x_2' = (1 -u(t) ) x_1. Page 11 second line switch order of dt and ] and the function g needs a ) at the end of its arguements. Remove the bounds on the control on Exercies 23.1 page 202 On page 212: Roughly speaking, this space consists of all functions square-integrable in time with first weak derivatives in space, which are also square-integrable. On page 242: Change max to min