Talk:Erdős–Pósa theorem
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Erdős–Pósa property as a special case of Robertson-Seymour theorem
[edit]"The special case where H is a triangle is equivalent to the Erdős–Pósa theorem." Does H really need to be a triangle? Can't it be any cycle? 147.229.208.56 (talk)
Answer: No, H cannot be any cycle. The case where H is a cycle of length j≥4 implies a different variant of the Erdős–Pósa theorem: For every positive integer k, every graph either contains at least k vertex-disjoint cycles of length at least j or it has a feedback vertex set of at most f(k) vertices that intersects every cycle of length at least j. Wikiwiswa (talk) 23:00, 26 March 2020 (UTC)