A unified Erd\H{o}s-P\'{o}sa theorem for cycles in graphs labelled by multiple abelian groups
Abstract
In 1965, Erd\H{o}s and P\'{o}sa proved that there is an (approximate) duality between the maximum size of a packing of cycles and the minimum size of a vertex set hitting all cycles. Such a duality does not hold for odd cycles, and Dejter and Neumann-Lara asked in 1988 to find all pairs of integers where such a duality holds for the family of cycles of length modulo . We characterise all such pairs, and we further generalise this characterisation to cycles in graphs labelled with a bounded number of abelian groups, whose values avoid a bounded number of elements of each group. This unifies almost all known types of cycles that admit such a duality, and it also provides new results. Moreover, we characterise the obstructions to such a duality in this setting, and thereby obtain an analogous characterisation for cycles in graphs embeddable on a fixed compact orientable surface.
Keywords
Cite
@article{arxiv.2209.09488,
title = {A unified Erd\H{o}s-P\'{o}sa theorem for cycles in graphs labelled by multiple abelian groups},
author = {J. Pascal Gollin and Kevin Hendrey and O-joung Kwon and Sang-il Oum and Youngho Yoo},
journal= {arXiv preprint arXiv:2209.09488},
year = {2026}
}
Comments
41 pages, 7 figures