Let G V A denote a simple connected directed graph and let n jV j m jAj where n m n A feedback arc set FAS of G denoted R G is a possibly empty set of arcs whose reversal makes G acyclic A minimum feedback arc set of G denoted R G is a FAS of minimum cardinality r G the computa tion of R G is called the FAS problem For every n let n denote the maximum over all digraphs G of order n of jR G j Berger and Shor have recently published an algorithm which for a given digraph G computes a FAS whose… Expand