FRAMES, A-PATHS, AND THE ERDŐS--PÓSA PROPERTY.

A key feature of Simonovits' proof of the classic Erdőos--Pósa theorem is a simple subgraph of the host graph, a frame, that determines the outcome of the theorem. We transfer this frame technique to A-paths. With it we deduce a simple proof of Gallai's theorem, although with a worse bound, and we verify the Erdős--Pósa property for long and for even A-paths. We also show that even A-paths do not have the edge-Erdős--Pósa property. [ABSTRACT FROM AUTHOR]