To convey an idea that is obvious in retrospect, an idea you can be confident in immediately
Solutions to hard puzzles are good examples of these. NP-problems, where finding a solution is (believed to be) exponentially harder than checking the correctness of it, is the extreme case.
Solutions to hard puzzles are good examples of these. NP-problems, where finding a solution is (believed to be) exponentially harder than checking the correctness of it, is the extreme case.