Feedback Set Problems

Not long ago, there appeared to be a consensus in the literature that feedback set problems, which originated from the area of combinational circuit design, were the least understood among all the classical combinatorial optimization problems due to the lack of positive results in efficient exact and approximating algorithms. This picture has been totally changed in recent years. Dramatic progress has occurred in developing approximation algorithms with provable performance; new bounds have been established one after the other and it is probably fair to say that feedback set problems are becoming among the most exciting frontend problems in combinatorial optimization.