The authors solved the traveling salesman problem. This isn't just a personal problem. Special cartridge in an attempt to solve this very problem. Defects in cutting such as these lead to a serious phase problem. Corrective actions are nothing but actions based on problem identification. Collaborative filtering is one of the techniques used for dealing with this problem. Malnutrition is a serious problem for Guinea. However, designing a divertor for a tokamak proved to be a very difficult design problem. None gives any indication of a problem. It appears as a blue screen with white letters telling of a problem. Researchers devised several methods for solving this problem. One such social problem is age discrimination. This creates a troublesome moral hazard problem. Desertification is a serious problem in Sudan. This is known as a hierarchy problem.