> So if I am concerned with what can be done in polynomial time, then why would I limit myself to Karp reductions? Because under Karp, SAT and UNSAT are widely

> So if I am concerned with what can be done in polynomial time, then why would I limit myself to Karp reductions? Because under Karp, SAT and UNSAT are widely different problems whereas under Cook, they're not. You can verify SAT in polynomial time. You can not do that for UNSAT.