Languages that are easier than their proofs

Languages in NP are presented for which it is harder to prove membership interactively than it is to decide this membership. Similarly, languages where checking is harder than computing membership are presented. Under assumptions about triple-exponential time, incoherent sets in NP are constructed. Without any assumptions, incoherent sets are constructed in DSPACE (n to the log n), yielding the first uncheckable and non-random-self-reducible sets in that space.<
>