In lecture 4 of topic 3 (Nov.8), the definition of G? and x? on slide 12 was wrong. The correct defenition of G? is: G? = the G level at which I would be just indifferent between contributing and not contributing. x? is not needed. A correct version of the lecture notes has been posted on the webpage: http://folk.uio.no/karineny/ECON4260/2011/Lecture4.pdf
(Due to coding issues, every ? is actually a star.)