Packing non-returning A-paths algorithmically

In this paper we present an algorithmic approach to packing A-paths. It is regarded as a generalization of Edmonds’ matching algorithm, however there is the significant difference that here we do not build up any kind of alternating tree. Instead we use the so-called 3-way lemma, which either provides augmentation, or a dual, or a subgraph which can be used for contraction. The method works in the general setting of packing non-returningA-paths. It also implies an ear-decomposition of criticals, as a generalization of the odd ear-decomposition of factor-critical graph.