‘Easy to verify’ has a special place in computer science and always had.
Like many NP-complete problems it is easy to verify that a solution of SAT is correct but it can be very hard to find one or prove one doesn’t exist unless the problem cooperates with you.
Like many NP-complete problems it is easy to verify that a solution of SAT is correct but it can be very hard to find one or prove one doesn’t exist unless the problem cooperates with you.