Due Tuesday March 11 at the beginning of lecture.
Important update: In problem 4.(a), recall that is a universal predicate for unary formulas, so if is the Gödel number of a formula in one free variable , then holds iff holds. Hence, asking that is finite is the same as asking that is finite. Actually, this is a serious typo:
is -complete. The set is -complete.
Sorry about this. Either ignore 4.(a), or try to show (for extra credit) that the set is -complete, or (for a much more challenging problem) that the corresponding set with “cofinite” is -complete.