> I find such summary ambiguous. Difficult for who? What is "solve"? The example given was finding a route on a map. Is any route a valid solution, or only the

> I find such summary ambiguous. Difficult for who? What is "solve"? The example given was finding a route on a map. Is any route a valid solution, or only the best one? Does the time differ for finding a route of the same quality, or does it differ only for how long it takes until the brain is satisfied with the solution?