It may not be the case in our universe. An O(n^2) algorithm is only faster than O(n^3) algorithm for an n > N (N may be 0). N may be so large that the problems

It may not be the case in our universe. An O(n^2) algorithm is only faster than O(n^3) algorithm for an n > N (N may be 0). N may be so large that the problems it solves faster take more time than the heat death of the universe.