P versus NP problem
P versus NP is one of the Millennium Problems, and of great interest to people working with computers and in mathematics. One way of asking it is, "Can every solved problem whose answer can be checked quickly by a computer, also be quickly solved by a computer?" Math problems are referred to as P or NP, whether they are solvable in a given finite set of time with the problem itself being the upper limit. P problems have their solution time bound to a polynomial and so are relatively fast for computers to solve, and so are considered "easy". NP problems are fast (and so "easy") for a computer to check, but are not necessarily easy to solve.