•Theorem [Stockmeyer] QBF is PSPACE complete
•
•Return to our proof:
reduction from QBF.
•
•Given QBF formula F, let s = {U}, where U = unary
•A = (A, UA), s.t. A =
{0,1}, UA = {1}
•Translate F (a QB formula) to f (an FO formula)
s.t. F is true iff A ² f [how ?]