“…Within the last decade, kidney exchange has received considerable attention in the computer science and operations research [1,2,3,6,8,10,11,13,15,16,17,32,40], economics [4,7,34,35,36,41] and medical [5,12,18,20,21,22,23,25,26,29,30,33,37,38,39] literature, with many of these papers being inter-disciplinary in nature. It has been observed that when only pairwise exchanges are permitted, an optimal solution can usually (depending of course on the definition of optimality) be found in polynomial time using maximum weight matching in a general graph (see e.g., [10] for more details).…”